O manejo florestal madeireiro é uma atividade que promove a manutenção da cobertura florestal em áreas de floresta primária no Brasil. Atualmente, as técnicas de manejo estão sendo aperfeiçoadas pelo desenvolvimento de novas tecnologias da área de geoprocessamento, como o Sistema Global de Posicionamento por Satélite (GNSS), Lidar (Ligth detection and ranging) aerotransportado (ALS) e Aeronaves Remotamente Pilotadas (ARPs). O objetivo geral deste trabalho é apresentar os princípios do manejo florestal de precisão aplicados para a região amazônica e avaliar a capacidade dos dados do Lidar na redução da intensidade amostral no inventário florestal. Para tal, foi utilizada uma área demonstrativa de manejo florestal de precisão localizada no campo experimental da Embrapa, no município de Rio Branco, Acre. O estudo foi desenvolvido em uma área contínua de 800 hectares, com presença de floresta primária do tipo umbrófila, aberta, com presença de palmeiras, bambu e manchas de floresta alta. Foram realizadas duas coletas de dados nesta área: o censo florestal das árvores com DAP >= 40 cm, com o qual calculou-se a área seccional de cada árvore; e o voo Lidar feito a uma altitude de 600 metros, com footprint de 30 cm e densidade de 14 pts.m2. A partir dos dados Lidar foram extraídas os modelos digitais de superfície (MDS), do terreno (MDT) e altura (MAD), e as métricas Altmd (altura média do dossel), rugosidade (desvio padrão da altura média do dossel), Altdossel (abertura do dossel a 15 metros), LAI (índice de área foliar) e LAIsub (LAI do sub-bosque - faixa entre 5 a 12 metros de altura). No capítulo 01, os dados foram analisados de forma a demonstrar a aplicação do Lidar no aperfeiçoamento das atividades técnicas do manejo florestal na amazônia, sendo elas: (i) macroplanejamento da Área de Manejo Florestal (AMF); (ii) microplanejamento do terreno e hidrografia da Unidade de Produção Anual (UPA); (iii) censo e amostragem florestal; (iv) planejamento da infraestrutura de exploração; e (v) monitoramento. Na análise dos dados do capítulo 02, foram feitas: (i) estimativa dos atributos estruturais derivados do inventário de campo e da nuvem de retornos Lidar para três tamanhos de célula; (ii) correlação de Pearson entre os atributos do campo e do dossel derivados do Lidar; (iii) análise de agrupamento para formação dos estratos pelo método de Ward; (iv) validação (ANOVA) e caracterização dos estratos (PCA); e (v) estimativa de redução da intensidade amostral por meio de uma simulação computacional. Como resultado, os mapas gerados mostram a acurácia e qualidade dos dados do Lidar para o mapeamento de unidades de produção anual dentro da área de manejo florestal, microzoneamento da topografia, modelagem da rede de drenagem, identificação de áreas de relevo acidentado, delimitação da APP e planejamento da infraestrutura de exploração respeitando as condições ambientais e potecial madeireiro da área de estudo. A altura média do dossel da floresta (Altmd), obtida com o Lidar, apresentou a maior correlação (r = 0,74) com a área basal e foi utilizada para estratificar a vegetação em quatro padrões de floresta, com diferença significativa entre eles para a variável de campo. A estratificação com a Altmd distinguiu bem a floresta quanto ao seu gradiente de variação estrutural e perfil de densidade da vegetação. A simulação do inventário estratificado versus o inventário inteiramente casualizado evidenciou a capacidade da variável Lidar Altmd em reduzir o número de parcelas em até 41% quando utilizado 4 estratos para uma mesma incerteza relativa de 10%. O uso de uma única métrica de dossel, derivada do Lidar, foi capaz de estratificar uma área de floresta tropical primária, além de gerar informações adicionais, como o índice de área foliar do sub-bosque e o modelo do terreno que podem auxiliar na tomada de decisão para o manejo, conservação e monitoramento de florestas tropicais. / Timber forest management is an activity that promotes the maintenance of forest cover in primary forest areas in Brazil. Currently, management techniques are being improved by the development of new geoprocessing technologies such as the Global Positioning Satellite System (GNSS), Airborne Lidar Scanning (ALS) and Remotely Piloted Aircraft (ARPs). The general objective of this work is to present the principles of precision forest management applied to the Amazon region and evaluate the reduction of sampling intensity in the forest inventory from vegetation stratification using Lidar variables. For this, was used a demonstration area of precision forest management located in the experimental field of Embrapa, in Rio Branco, Acre. The study was located in a continuous area of 800 hectares, in open ombrphylous forest with presence of palms, bamboo and dense forest portions. Two data collections were carried out in this area: the census inventory of trees with DBH >= 40 cm, which the sectional area of each tree was calculated; and the Lidar flight made at an altitude of 600 meters, with footprint of 30 cm and density of 14 pts.m2. From the Lidar data were processed the digital surface models (DSM), terrain (DTM) and height (CHM), CHmean (average canopy height), roughness (standard deviation of the canopy), CHopenness (canopy openness of 15 meters), LAI (leaf area index) and LAIunder (LAI between 5 to 12 meters of height). In chapter 01, the data were analyzed in order to demonstrate the application of Lidar to improve the technical activities of the forest management in the Amazon, being: (i) macroplanning of the forest management area (AMF); (ii) micro-planning of the land and hydrography of the annual production unit (UPA); (iii) forest census and sampling; (iv) exploration infrastructure planning; and (v) monitoring. The analysis performed on the data of chapter 02 were: (i) estimation of the structural attributes derived from the field inventory and of the return cloud Lidar for three cell sizes; (ii) Pearson correlation between the field and canopy attributes derived from the Lidar; (iii) cluster analysis for classify strata by the Ward method; (iv) validation (ANOVA) and characterization of stratas (PCA); and (v) reduction of sample estimation intensity by a computer simulation. As result, the generated maps show the accuracy and quality of the Lidar data for mapping of annual production units within the area of forest management, microzoning of the topography, drainage network modeling, identification of rugged relief areas, APP boundary and planning the exploration infrastructure respecting the environmental conditions and timber potential of the study area. The average height of the forest canopy (CHmean), obtained with the Lidar, presented the highest correlation (r = 0.74) with the basal area and was used to stratify the vegetation in four forest patterns, with significant difference between them for the field variable. The stratification with CHmean distinguished the forest well for its structural variation gradient and vegetation density profile. The simulation of the stratified inventory versus the completely randomized inventory evidenced the ability of the Lidar Altmd variable to reduce the number of plots by up to 41% when using 4 strata for the same relative uncertainty of 10%. The use of a single canopy metric derived from Lidar was able to stratify an area of primary rainforest, in addition to generating additional information such as understory leaf area index and the terrain model that can assist in decision making for management, conservation and monitoring of tropical forests.

As nuvens cirrus cobrem uma grande fração das latitudes tropicais e desempenham um papel importante no balanço de radiação da Terra. As propriedades ópticas, altitude, extensão vertical, e cobertura horizontal de nuvens controlam sua forçante radiativa. Além disso, nuvens cirrus tropicais podem influenciar a distribuição vertical do aquecimento radiativo na tropopausa tropical e pesquisas recentes também apontam para um aumento do vapor de água estratosférico ligado principalmente à ocorrência de nuvens cirrus na camada da tropopausa tropical (TTL). Apesar de sua importância, estudos relatando propriedades de nuvens cirrus sobre florestas tropicais como a Amazônia são ainda escassos. A maioria estão baseados em imagens de satélites de órbita polar que não fornecem informações sobre o ciclo diurno, nem sobre a estrutura vertical destas nuvens. Ao mesmo tempo, os estudos com lidar em solo são restritos a poucos estudos de caso, em geral associados a campanhas de campo de curta duração. Este panorama começou a mudar em 2011 com a instalação do sistema lidar do Laboratório de Física Atmosférica do IF-USP próximo à cidade de Manaus, Brasil. Neste trabalho, um conjunto de um ano de dados (de julho de 2011 a junho de 2012) foi utilizado para caracterizar as propriedades macro, microfísicas e ópticas das nuvens cirrus sobre a região amazônica e, posteriormente, calcular o papel que essas nuvens têm no balanço radiativo do planeta. Para tanto, foi desenvolvido um algoritmo automático para detectar as nuvens e para obter as propriedades ópticas, incluindo a correção de múltiplo-espalhamento. As forçantes radiativas foram estimadas com dois modelos diferentes, a partir dos perfis de extinção medido com o lidar e de uma parametrização para estimar o raio efetivo dos cristais de gelo. Nossos resultados mostraram que as nuvens cirrus na alta troposfera foram mais frequentes na Amazônia do que relatado previamente em outras regiões tropicais. A frequência de ocorrência foi de 88 % durante a estação chuvosa e não inferior a 50 % durante a estação seca. O ciclo diurno mostrou um mínimo ao redor do meio-dia local e máximo durante o final da tarde, associado ao ciclo diurno da precipitação. Os valores médios das alturas de topo e base, da espessura e da profundidade óptica da nuvem foram de 14,3 +- 1,9 (desv. pad.) km, 12,9 +- 2,2 km, 1,4 +- 1,1 km e 0,25 +- 0,46, respectivamente. As nuvens cirrus foram encontradas em temperaturas de até -90 degC, com 6 % ocorrendo acima da tropopausa. A distribuição vertical não se mostrou uniforme, e nuvens cirrus finas (0,03 < COD < 0,3) e subvisuais (COD < 0,03) ocorreram mais frequentemente nas proximidades da tropopausa. A razão lidar média foi de 23,3 +- 8,0 sr. Contudo, para as nuvens cirrus subvisuais foi encontrada uma distribuição bimodal com um pico secundário em torno de 44 sr, sugerindo uma composição mista dos cristais de gelo. Não foi encontrada uma dependência da razão lidar com a temperatura da nuvem (altitude), indicando que as nuvens estão verticalmente bem misturadas. A frequência de ocorrência relativa das camadas de nuvens cirrus classificadas como subvisuais foi de 41,6 %, enquanto que 37,8 % foram cirrus finos e 20,5 % de cirrus opacos (COD > 0,3), com uma superposição média de 1,41 +- 0,63 camadas por perfil. Assim, na Amazônia central não ocorre apenas uma alta frequência de nuvens cirrus, mas também uma grande fração de nuvens cirrus subvisuais, o que pode estar contaminando as medidas de fotômetros solares e sensores orbitais. As propriedades medidas foram utilizadas no cálculo da forçante radiativa das nuvens cirrus (CRF) e dos perfis da taxa de aquecimento da atmosfera, em detalhe pelo libRadtran e aproximadamente pelo modelo de Corti e Peter (modelo CP). Com tamanha frequência de ocorrência e residindo tão alto sobre a intocada floresta Amazônica (albedo ~ 0,12), essas nuvens produziram uma CRF líquida no topo da atmosfera e na superfície (TOA e BOA) de +15,3 +- 0,4 e -3,7 +- 0,2 W m-2, respectivamente, muito mais intenso do que o estimado sobre a Europa (0,9 a 1,7 W m-2 no TOA). Cirrus opticamente mais espessas, em geral, apresentaram CRF líquido maior, com CRF instantâneo atingindo valores máximos (mínimos) de 140 (-65) W m-2 para o período noturno (diurno) no TOA. Juntos, os perfis verticais com COD_Coluna > 0,3 foram responsáveis por cerca de 72 % (62 %) do CRF líquido no TOA (BOA), o que significa que uma importante fração do CRF é gerada por cirrus opticamente mais finos (COD_Coluna < 0,3), que são mais difíceis de serem detectados por radares e instrumentos passivos a bordo de satélites. O ciclo diurno da profundidade óptica das nuvens cirrus teve reflexo em sua forçante radiativa. Observamos um ciclo diurno do valor médio da CRF líquida no TOA (BOA), que vaiou entre 1,7 (-23) W m-2 à tarde e 47 (3,1) W m-2 durante a noite. As nuvens cirrus promovem um aquecimento aproximadamente constante de 1,2 K dia-1 no perfil vertical entre 8 e 18 km (dentro da nuvem), mas com valores instantâneos superiores a 10 K dia-1 para porções da nuvem com alto IWC. Acredita-se que esse perfil de aquecimento gerado pelas nuvens cirrus tenha um papel importante na circulação da alta troposfera/baixa estratosfera, gerando um fluxo ascendente médio de massa de ar entre 2 e 15 kg m-2 dia-1 para altitudes entre 13 e 16,5 km, contribuindo para a manutenção da camada de cirrus próximo da tropopausa tropical. / Cirrus clouds cover a large fraction of tropical latitudes and play an important role in the Earth\'s radiation balance. Their optical properties, altitude, vertical extension, and horizontal cover control their radiative effect. In addition, tropical cirrus clouds can influence the vertical distribution of radiative heating near the tropopause, and recent research associate the moistening of the lower stratosphere with the occurrence of cirrus clouds in the tropical tropopause layer (TTL). Despite their importance, studies describing the properties of cirrus clouds over tropical forests like the Amazon are still scarce. Most studies are based on images from polar orbiting satellites, which do not give information on the diurnal cycle nor on the vertical structure of these clouds. At the same time, the studies based on ground-based lidars are restricted to a few case studies, from short-term field campaigns. This panorama started to change in 2011 with the installation of a lidar system from the Laboratory of Atmospheric Physics of IF-USP near the city of Manaus, Brazil. In this study, data from July 2011 to June 2012 was used to characterize the macro, microphysical and optical properties of cirrus clouds over the Amazon region, and then to calculate the role of those clouds in the radiative balance of the planet. An automatic algorithm was developed to detect the cloud layers and to obtain the optical properties, already considering the multiple-scattering correction. Two different models, using as input the measured extinction profiles and a parameterization for the ice crystals effective radius, were used to estimate the cirrus radiative effect. Our results showed that cirrus clouds are more frequent in Amazonia than in other tropical regions. The frequency of occurrence was 88 % during the rainy season and not less than 50 % during the dry season. The diurnal cycle showed a minimum around local noon and a maximum around late afternoon, associated with the diurnal cycle of precipitation. The average values of the top and cloud base heights, thickness, and optical depth were 14.3 +- 1.9 km, 12.9 +- 2.2 km, 1.4 +- 1.1 km, and 0.25 +- 0.46, respectively. Cirrus clouds were found at temperatures as low as -90 degC, with 6 % occurring above the tropopause. The vertical distribution was not uniform, and thin cirrus (0.03 < COD <0.3) and subvisible (COD <0.03) were more frequent in the vicinity of the tropopause. The mean lidar-ratio was 23.3 +- 8.0 sr. However, for the subvisible clouds a bimodal distribution with a secondary peak at about 44 sr was found, suggesting a mixture of ice crystals habits. No dependence of the lidar-ratio with temperature (altitude) was found, suggesting these clouds are well mixed vertically. The relative frequency of occurrence of cirrus layers classified as subvisible was 41.6 %, while 37.8 % were thin cirrus and 20.5 % opaque cirrus (COD > 0.3), with an average overlap of 1.41 +- 0.63 layers per profile. Therefore, in central Amazonia, there is not only a high incidence of cirrus clouds, but also a large fraction of subvisible clouds, which may be contaminating the measurements of sunphotometers and satellite sensors. These measured properties were used for the calculation of the cirrus radiative forcing (CRF) and the heating rate profiles, in detail with libRadtran, and approximately with the model of Corti and Peter (modelo CP). Given their high frequency of occurrence and location at high altitude over the pristine Amazon forest (albedo ~ 0,12), these clouds produced a net CRF at the top and bottom of the atmosphere (TOA and BOA) of +15.3 +- 0.4 and -3.7 +- 0.2 W m-2, respectively. This is greater than what was found over Europe (0.9, to 1.7 W m-2 at TOA). Optically thicker cirrus usually had larger CRF, with instantaneous CRF reaching peak (minimum) values of 140 (-65) W m-2 for the nocturnal (diurnal) period at TOA. The vertical profiles with COD_Column> 0.3 were responsible for about 72 % (62 %) of the net CRF at TOA (BOA), which means that a significant fraction of the cirrus CRF is generated by optically thin cirrus (COD_Column <0.3), which are more difficult to detect by radars and passive instruments on satellites. The diurnal cycle of the cirrus clouds optical depth had influence in its radiative forcing. We observed a diurnal cycle of the mean value of net CRF at TOA (BOA), which ranged from 1.7 (-23) W m-2 in the afternoon to 47 (3.1) W m-2 at night. The heating rates associated with these cirrus clouds were approximately constant, with 1.2 K day-1 from 8 to 18 km (within the cloud), but with instantaneous values that reached values higher than 10 K day-1 for portions with higher IWC. It is believed that this warming profile plays an important role in the circulation of the upper troposphere/low stratosphere, generating an average air mass flux between 2 and 15 kg m-2 day-1 for altitudes between 13 and 16.5 km, a positive feedback for the maintenance of the cirrus layer near the tropical tropopause.

As nuvens cirrus cobrem uma grande fração das latitudes tropicais e desempenham um papel importante no balanço de radiação da Terra. As propriedades ópticas, altitude, extensão vertical, e cobertura horizontal de nuvens controlam sua forçante radiativa. Além disso, nuvens cirrus tropicais podem influenciar a distribuição vertical do aquecimento radiativo na tropopausa tropical e pesquisas recentes também apontam para um aumento do vapor de água estratosférico ligado principalmente à ocorrência de nuvens cirrus na camada da tropopausa tropical (TTL). Apesar de sua importância, estudos relatando propriedades de nuvens cirrus sobre florestas tropicais como a Amazônia são ainda escassos. A maioria estão baseados em imagens de satélites de órbita polar que não fornecem informações sobre o ciclo diurno, nem sobre a estrutura vertical destas nuvens. Ao mesmo tempo, os estudos com lidar em solo são restritos a poucos estudos de caso, em geral associados a campanhas de campo de curta duração. Este panorama começou a mudar em 2011 com a instalação do sistema lidar do Laboratório de Física Atmosférica do IF-USP próximo à cidade de Manaus, Brasil. Neste trabalho, um conjunto de um ano de dados (de julho de 2011 a junho de 2012) foi utilizado para caracterizar as propriedades macro, microfísicas e ópticas das nuvens cirrus sobre a região amazônica e, posteriormente, calcular o papel que essas nuvens têm no balanço radiativo do planeta. Para tanto, foi desenvolvido um algoritmo automático para detectar as nuvens e para obter as propriedades ópticas, incluindo a correção de múltiplo-espalhamento. As forçantes radiativas foram estimadas com dois modelos diferentes, a partir dos perfis de extinção medido com o lidar e de uma parametrização para estimar o raio efetivo dos cristais de gelo. Nossos resultados mostraram que as nuvens cirrus na alta troposfera foram mais frequentes na Amazônia do que relatado previamente em outras regiões tropicais. A frequência de ocorrência foi de 88 % durante a estação chuvosa e não inferior a 50 % durante a estação seca. O ciclo diurno mostrou um mínimo ao redor do meio-dia local e máximo durante o final da tarde, associado ao ciclo diurno da precipitação. Os valores médios das alturas de topo e base, da espessura e da profundidade óptica da nuvem foram de 14,3 +- 1,9 (desv. pad.) km, 12,9 +- 2,2 km, 1,4 +- 1,1 km e 0,25 +- 0,46, respectivamente. As nuvens cirrus foram encontradas em temperaturas de até -90 degC, com 6 % ocorrendo acima da tropopausa. A distribuição vertical não se mostrou uniforme, e nuvens cirrus finas (0,03 < COD < 0,3) e subvisuais (COD < 0,03) ocorreram mais frequentemente nas proximidades da tropopausa. A razão lidar média foi de 23,3 +- 8,0 sr. Contudo, para as nuvens cirrus subvisuais foi encontrada uma distribuição bimodal com um pico secundário em torno de 44 sr, sugerindo uma composição mista dos cristais de gelo. Não foi encontrada uma dependência da razão lidar com a temperatura da nuvem (altitude), indicando que as nuvens estão verticalmente bem misturadas. A frequência de ocorrência relativa das camadas de nuvens cirrus classificadas como subvisuais foi de 41,6 %, enquanto que 37,8 % foram cirrus finos e 20,5 % de cirrus opacos (COD > 0,3), com uma superposição média de 1,41 +- 0,63 camadas por perfil. Assim, na Amazônia central não ocorre apenas uma alta frequência de nuvens cirrus, mas também uma grande fração de nuvens cirrus subvisuais, o que pode estar contaminando as medidas de fotômetros solares e sensores orbitais. As propriedades medidas foram utilizadas no cálculo da forçante radiativa das nuvens cirrus (CRF) e dos perfis da taxa de aquecimento da atmosfera, em detalhe pelo libRadtran e aproximadamente pelo modelo de Corti e Peter (modelo CP). Com tamanha frequência de ocorrência e residindo tão alto sobre a intocada floresta Amazônica (albedo ~ 0,12), essas nuvens produziram uma CRF líquida no topo da atmosfera e na superfície (TOA e BOA) de +15,3 +- 0,4 e -3,7 +- 0,2 W m-2, respectivamente, muito mais intenso do que o estimado sobre a Europa (0,9 a 1,7 W m-2 no TOA). Cirrus opticamente mais espessas, em geral, apresentaram CRF líquido maior, com CRF instantâneo atingindo valores máximos (mínimos) de 140 (-65) W m-2 para o período noturno (diurno) no TOA. Juntos, os perfis verticais com COD_Coluna > 0,3 foram responsáveis por cerca de 72 % (62 %) do CRF líquido no TOA (BOA), o que significa que uma importante fração do CRF é gerada por cirrus opticamente mais finos (COD_Coluna < 0,3), que são mais difíceis de serem detectados por radares e instrumentos passivos a bordo de satélites. O ciclo diurno da profundidade óptica das nuvens cirrus teve reflexo em sua forçante radiativa. Observamos um ciclo diurno do valor médio da CRF líquida no TOA (BOA), que vaiou entre 1,7 (-23) W m-2 à tarde e 47 (3,1) W m-2 durante a noite. As nuvens cirrus promovem um aquecimento aproximadamente constante de 1,2 K dia-1 no perfil vertical entre 8 e 18 km (dentro da nuvem), mas com valores instantâneos superiores a 10 K dia-1 para porções da nuvem com alto IWC. Acredita-se que esse perfil de aquecimento gerado pelas nuvens cirrus tenha um papel importante na circulação da alta troposfera/baixa estratosfera, gerando um fluxo ascendente médio de massa de ar entre 2 e 15 kg m-2 dia-1 para altitudes entre 13 e 16,5 km, contribuindo para a manutenção da camada de cirrus próximo da tropopausa tropical. / Cirrus clouds cover a large fraction of tropical latitudes and play an important role in the Earth\'s radiation balance. Their optical properties, altitude, vertical extension, and horizontal cover control their radiative effect. In addition, tropical cirrus clouds can influence the vertical distribution of radiative heating near the tropopause, and recent research associate the moistening of the lower stratosphere with the occurrence of cirrus clouds in the tropical tropopause layer (TTL). Despite their importance, studies describing the properties of cirrus clouds over tropical forests like the Amazon are still scarce. Most studies are based on images from polar orbiting satellites, which do not give information on the diurnal cycle nor on the vertical structure of these clouds. At the same time, the studies based on ground-based lidars are restricted to a few case studies, from short-term field campaigns. This panorama started to change in 2011 with the installation of a lidar system from the Laboratory of Atmospheric Physics of IF-USP near the city of Manaus, Brazil. In this study, data from July 2011 to June 2012 was used to characterize the macro, microphysical and optical properties of cirrus clouds over the Amazon region, and then to calculate the role of those clouds in the radiative balance of the planet. An automatic algorithm was developed to detect the cloud layers and to obtain the optical properties, already considering the multiple-scattering correction. Two different models, using as input the measured extinction profiles and a parameterization for the ice crystals effective radius, were used to estimate the cirrus radiative effect. Our results showed that cirrus clouds are more frequent in Amazonia than in other tropical regions. The frequency of occurrence was 88 % during the rainy season and not less than 50 % during the dry season. The diurnal cycle showed a minimum around local noon and a maximum around late afternoon, associated with the diurnal cycle of precipitation. The average values of the top and cloud base heights, thickness, and optical depth were 14.3 +- 1.9 km, 12.9 +- 2.2 km, 1.4 +- 1.1 km, and 0.25 +- 0.46, respectively. Cirrus clouds were found at temperatures as low as -90 degC, with 6 % occurring above the tropopause. The vertical distribution was not uniform, and thin cirrus (0.03 < COD <0.3) and subvisible (COD <0.03) were more frequent in the vicinity of the tropopause. The mean lidar-ratio was 23.3 +- 8.0 sr. However, for the subvisible clouds a bimodal distribution with a secondary peak at about 44 sr was found, suggesting a mixture of ice crystals habits. No dependence of the lidar-ratio with temperature (altitude) was found, suggesting these clouds are well mixed vertically. The relative frequency of occurrence of cirrus layers classified as subvisible was 41.6 %, while 37.8 % were thin cirrus and 20.5 % opaque cirrus (COD > 0.3), with an average overlap of 1.41 +- 0.63 layers per profile. Therefore, in central Amazonia, there is not only a high incidence of cirrus clouds, but also a large fraction of subvisible clouds, which may be contaminating the measurements of sunphotometers and satellite sensors. These measured properties were used for the calculation of the cirrus radiative forcing (CRF) and the heating rate profiles, in detail with libRadtran, and approximately with the model of Corti and Peter (modelo CP). Given their high frequency of occurrence and location at high altitude over the pristine Amazon forest (albedo ~ 0,12), these clouds produced a net CRF at the top and bottom of the atmosphere (TOA and BOA) of +15.3 +- 0.4 and -3.7 +- 0.2 W m-2, respectively. This is greater than what was found over Europe (0.9, to 1.7 W m-2 at TOA). Optically thicker cirrus usually had larger CRF, with instantaneous CRF reaching peak (minimum) values of 140 (-65) W m-2 for the nocturnal (diurnal) period at TOA. The vertical profiles with COD_Column> 0.3 were responsible for about 72 % (62 %) of the net CRF at TOA (BOA), which means that a significant fraction of the cirrus CRF is generated by optically thin cirrus (COD_Column <0.3), which are more difficult to detect by radars and passive instruments on satellites. The diurnal cycle of the cirrus clouds optical depth had influence in its radiative forcing. We observed a diurnal cycle of the mean value of net CRF at TOA (BOA), which ranged from 1.7 (-23) W m-2 in the afternoon to 47 (3.1) W m-2 at night. The heating rates associated with these cirrus clouds were approximately constant, with 1.2 K day-1 from 8 to 18 km (within the cloud), but with instantaneous values that reached values higher than 10 K day-1 for portions with higher IWC. It is believed that this warming profile plays an important role in the circulation of the upper troposphere/low stratosphere, generating an average air mass flux between 2 and 15 kg m-2 day-1 for altitudes between 13 and 16.5 km, a positive feedback for the maintenance of the cirrus layer near the tropical tropopause.

The measurement of topography is a key aspect of geomorphology research, and the prevalence of high resolution topographic data predominantly from Light Detection And Ranging (LiDAR) in the past decade has facilitated a revolution in the quantitative study of planetary surface processes. From this increased quality of data, many techniques have been developed to quantify processes occurring at diverse spatial and temporal scales; from the flow of material down a hill-slope to the uplift and subsequent erosion of mountain ranges. Such insights have identified signatures of processes imprinted on landscapes. These include physical processes such as wildfires and landslides, biological processes such as animal burrowing and tree throw, in addition to tectonic uplift and large scale sediment transport. These signatures are observed in both the morphology of hill-slopes and their connection to the channel network, thereby allowing measures of topography to provide quantitative measures of the rates of processes shaping the Earth’s surface. This thesis is concerned with the development and application of reproducible topographic analysis techniques, to yield new insights into hill-slope sediment transport and to provide accurate metrics for quantifying hill-slope properties, including hill-slope length (LH) and relief (R). The measurement of hill-slope length can be performed through the inversion of drainage density, or the analysis of slope-area plots. However, in Chapter 3 I present a method which quantifies the length of hill-slopes through the generation of hill-slope flow paths. The flow path method is shown to be the most reliable of these methods, and is able to provide measurements of the properties of individual hill-slopes, rather than the basin or landscape averaged techniques commonly employed. The topographic predictions of the LH-R relationship of the nonlinear sediment flux law, stating that the rate of sediment transport is nonlinearly dependent on hill-slope gradient, are also tested and contrasted with the predictions of a linear sediment flux law. This provides the first purely topography based test of a sediment flux law. Through the fitting of a prediction of the nonlinear flux derived model to these measurements of hill-slope length and relief, the critical gradient of each landscape, a key parameter in the nonlinear sediment flux law, is also constrained. A nondimensional framework for erosion rate and relief, which allows the comparison of hill-slopes with differing properties in order to identify landscape transience is presented in Chapter 4. This analysis technique builds upon the work performed in Chapter 3, utilizing similar measurements of hill-slope properties, including hill-slope length and relief. The software produced alongside this chapter is shown to reproduce the results of previous studies which have employed this technique. The method is employed on a new landscape in Coweeta, North Carolina where subtle evidence of topographic decay is presented, consistent with models of Miocene topographic rejuvenation in this location. A detailed sensitivity analysis of the technique is performed, highlighting the need for careful parameterization of any analysis, to ensure meaningful results. This method is also employed to estimate an average critical gradient for each landscape, presenting more evidence building upon the evidence presented in Chapter 3 that a broad range of critical gradients exist for any given landscape. The work presented in Chapter 5 attempts to constrain the limits of the geomorphic analyses presented in the previous chapters, when they are applied to low resolution topographic data. A series of topographic datasets are generated at resolutions ranging from 1 to 30 meters upon which topographic analyses are performed. I test two common channel extraction algorithms and find that a simple geometric method, which identifies tangential curvature thresholds in the landscape, provides a more accurate representation of the channel network in low resolution topographic data than a process based method which identifies the topographic signature of channel initiation. The measurement of curvature is also evaluated, and alongside the estimation of diffusivity, is shown to be sensitive to data resolution, however landscape properties also exhibit a strong control on these measurements, where the larger scale curvature signal of Gabilan Mesa, California is more robust than the sharp ridgelines of Santa Cruz Island, California. Finally, the techniques developed in Chapter 3 to measure hill-slope length and relief are tested and are shown to be robust at grid sizes up to 30 meters, with the caveat that an accurate channel network can be constrained.

Airborne multi-sensor imaging is increasingly used to examine vegetation properties. The advantage of using multiple types of sensor is that each detects a different feature of the vegetation, so that collectively they provide a detailed understanding of the ecological pattern. Specifically, Light Detection And Ranging (LiDAR) devices produce detailed point clouds of where laser pulses have been backscattered from surfaces, giving information on vegetation structure; hyperspectral sensors measure reflectances within narrow wavebands, providing spectrally detailed information about the optical properties of targets; while aerial photographs provide high spatial-resolution imagery so that they can provide more feature details which cannot be identified from hyperspectral or LiDAR intensity images. Using a combination of these sensors, effective techniques can be developed for mapping species and inferring leaf physiological processes at ITC-level. Although multi-sensor approaches have revolutionised ecological research, their application in mapping individual tree crowns is limited by two major technical issues: (a) Multi-sensor imaging requires all images taken from different sensors to be co-aligned, but different sensor characteristics result in scale, rotation or translation mismatches between the images, making correction a pre-requisite of individual tree crown mapping; (b) reconstructing individual tree crowns from unstructured raw data space requires an accurate tree delineation algorithm. This thesis develops a schematic way to resolve these technical issues using the-state-of-the-art computer vision algorithms. A variational method, called NGF-Curv, was developed to co-align hyperspectral imagery, LiDAR and aerial photographs. NGF-Curv algorithm can deal with very complex topographic and lens distortions efficiently, thus improving the accuracy of co-alignment compared to established image registration methods for airborne data. A graph cut method, named MCNCP-RNC was developed to reconstruct individual tree crowns from fully integrated multi-sensor imagery. MCNCP-RNC is not influenced by interpolation artefacts because it detects trees in 3D, and it detects individual tree crowns using both hyperspectral imagery and LiDAR. Based on these algorithms, we developed a new workflow to detect species at pixel and ITC levels in a temperate deciduous forest in the UK. In addition, we modified the workflow to monitor physiological responses of two oak species with respect to environmental gradients in a Mediterranean woodland in Spain. The results show that our scheme can detect individual tree crowns, find species and monitor physiological responses of canopy leaves.

Orientador: Mauricio Galo / Resumo: Um Levantamento Hidrográfico (LH) tem como principal meta a obtenção de dados para a edição e atualização de documentos náuticos, estes, voltados à segurança das atividades de navegação. Objetivando padronizar parâmetros de incerteza das cartas náuticas, a Organização Hidrográfica Internacional (OHI) define níveis mínimos de confiança para diferentes ordens. A sugestão dessas especificações foi internalizada pela Marinha do Brasil, responsável pela produção das cartas náuticas brasileiras, na NORMAM-25. Um desses parâmetros é a Incerteza Vertical Total máxima permitida, um indicador de qualidade da medição da profundidade. A informação de profundidade influencia no calado máximo permitido a uma embarcação para transitar em uma região com segurança, o que pode impactar inclusive nas limitações de transações comerciais em terminais portuários, uma vez que as profundidades estimadas com acurácia potencializam os parâmetros de operação dos portos. Por se tratar de um ambiente dinâmico, seja por ação da própria natureza ou devido a atividades antrópicas, a atualização de uma carta náutica deve ser uma preocupação constante. Como complemento à tradicional técnica de levantamento por meio de um ecobatímetro acoplado a embarcações, há a opção de se realizar um LH com o emprego da tecnologia LiDAR (Light Detection And Ranging) a partir de aeronaves, por meio de um aerolevantamento batimétrico por LiDAR (ALB – Airborne LASER Bathymetry), que operam com pulsos LASER na região verde do e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A Hydrographic Survey (HS) has as main goal to obtain data for editing and updating nautical documents, these, focused on the safety of navigation. In order to establish a standard of uncertainty parameters for nautical charts, the International Hydrographic Organization (IHO) defines minimum levels of confidence for different orders. The suggestion of these specifications was acknowledged by the Brazilian Navy, institution responsible to produce Brazilian nautical charts, as described in NORMAM-25. One such parameter is the maximum allowed Total Vertical Uncertainty, a quality indicator of the depth measurement. Depth information influences the maximum operational draft for a vessel to safely travel in a region, causing impact on port operations and limiting the commercial transactions. Accurately estimated depths enhance the operational parameters of the ports. Due to the aim of representing a dynamic environment, whether as consequence of the action of nature itself or because of anthropic activities, updating a nautical chart must be a constant concern. As a complement to the traditional survey technique conducted with a boat-coupled echosounder, there is the option of performing a HS using LiDAR (Light Detection And Ranging) technology from aircraft, through LiDAR aerial bathymetry (ALB - Airborne LASER Bathymetry), which operate with LASER pulses in the green region of the electromagnetic spectrum. Considering these points, this work analyzed the differences between the... (Complete abstract click electronic access below) / Mestre

The use of digital three-dimensional (3D) data has increased over the last two decades as private and public firms have begun to realize its utility. Mobile Terrestrial Laser Scanning (MTLS) or Mobile Mapping Systems (MMS), which utilizes LiDAR (Light Detection and Ranging) data collection from a moving platform along with advances in positioning systems—e.g., Global Navigation Satellite Systems (GNSS), Inertial Navigation Systems (INS), and Distance Measurement Instruments (DMIs)—have paved the way for efficient, abundant, and accurate 3D data collection. Validation and control targets are vital to ensure relative and/or absolute accuracy for MTLS projects. The focus of this dissertation is to evaluate several types of targets and the positional spacing of said targets for MTLS.<div><br></div><div>A mostly planar two-dimensional (2D) targeting system (painted target on ground) is commonly used to constrain, register, and validate the 3D point clouds from MTLS. In this dissertation, 3D objects—a sphere and a cube—were evaluated with varied angles of incidence and point densities as more appropriate alternatives to constrain and validate the 3D MTLS point clouds. Next, a planar circular 2D target—with the use of the raw intensity of the LiDAR pulse as another measured dimension—was evaluated as a proof of concept to also constrain and validate 3D LiDAR data. A third and final component of this dissertation explored analyses of INS data to determine the positional spacing of control and validation targets in MTLS projects to provide maximum accuracy for all data points.<br></div>

abstract: Laser radars or lidar’s have been used extensively to remotely study winds within the atmospheric boundary layer and atmospheric transport. Lidar sensors have become an important tool within the meteorology and the wind energy community. For example, Doppler lidars are used frequently in wind resource assessment, wind turbine control as well as in atmospheric science research. A Time of Flight based (ToF) direct detection lidar sensor is used in vehicles to navigate through complex and dynamic environments autonomously. These optical sensors are used to map the environment around the car accurately for perception and localization tasks that help achieve complete autonomy. This thesis begins with a detailed discussion on the fundamentals of a Doppler lidar system. The laser signal flow path to and from the target, the optics of the system and the core signal processing algorithms used to extract velocity information, were studied to get closer to the hardware of a Doppler lidar sensor. A Doppler lidar simulator was built to study the existing signal processing algorithms to detect and estimate doppler frequency, and radial velocity information. Understanding the sensor and its processing at the hardware level is necessary to develop new algorithms to detect and track specific flow structures in the atmosphere. For example, the aircraft vortices have been a topic of extensive research and doppler lidars have proved to be a valuable sensor to detect and track these coherent flow structures. Using the lidar simulator a physics based doppler lidar vortex algorithm is tested on simulated data to track a pair of counter rotating aircraft vortices. At a system level the major components of a time of flight lidar is very similar to a Doppler lidar. The fundamental physics of operation is however different. While doppler lidars are used for radial velocity measurement, ToF sensors as the name suggests provides precise depth measurements by measuring time of flight between the transmitted and the received pulses. The second part of this dissertation begins to explore the details of ToF lidar system. A system level design, to build a ToF direct detection lidar system is presented. Different lidar sensor modalities that are currently used with sensors in the market today for automotive applications were evaluated and a 2D MEMS based scanning lidar system was designed using off-the shelf components. Finally, a range of experiments and tests were completed to evaluate the performance of each sub-component of the lidar sensor prototype. A major portion of the testing was done to align the optics of the system and to ensure maximum field of view overlap for the bi-static laser sensor. As a laser range finder, the system demonstrated capabilities to detect hard targets as far as 32 meters. Time to digital converter (TDC) and an analog to digital converter (ADC) was used for providing accurate timing solutions for the lidar prototype. A Matlab lidar model was built and used to perform trade-off studies that helped choosing components to suit the sensor design specifications. The size, weight and cost of these lidar sensors are still very high and thus making it harder for automotive manufacturers to integrate these sensors into their vehicles. Ongoing research in this field is determined to find a solution that guarantees very high performance in real time and lower its cost over the next decade as components get cheaper and can be seamlessly integrated with cars to improve on-road safety. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2018

In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions in the field and a few years must pass before accumulating reliable crash data. This is a time-consuming approach and there remains uncertainty in the crash data due to the random nature of crash occurrences. The Surrogate Safety Assessment Model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative under study is modeled and no physical installation of the alternative is needed. Hence, the method using a simulation software along with SSAM consumes less time compared to other traditional safety analysis methods that may require a physical installation of the new alternative and a long wait time for data collection. The purpose of this study is to evaluate if SSAM can be used to assess the safety of a highway segment or an intersection in term of the number and type of conflicts and to compare the safety effects of multiple access management alternatives with less time, less cost and less uncertainty than the traditional safety analysis methods. To meet the purpose of the study, two study sections, one on University Parkway in Orem and Provo and the other on Main Street in American Fork were selected and analyzed in this research. Based on the findings from the calibration of SSAM on the University Parkway study section, an evaluation of the effect of converting a TWLTL median into a raised median on a section of Main Street (US-89) from 300 West to 500 East in American Fork was performed using SSAM working on VISSIM simulation's trajectory files of the study section. This evaluation study was conducted to show how SSAM could be used to evaluate the effect of access management alternatives using surrogate safety measures. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume. Approximately a 32 to 50 percent reduction in the number of crossing conflicts was achieved when a raised median was used in lieu of a TWLTL median at the Main Street study section.

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2008