Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-14T11:32:02Z No. of bitstreams: 1 TELMA LÚCIA BEZERRA ALVES - TESE (PPGRN) 2016.pdf: 11238465 bytes, checksum: 7f1bc917d37a959d86daf700437c86cd (MD5) / Made available in DSpace on 2018-06-14T11:32:02Z (GMT). No. of bitstreams: 1 TELMA LÚCIA BEZERRA ALVES - TESE (PPGRN) 2016.pdf: 11238465 bytes, checksum: 7f1bc917d37a959d86daf700437c86cd (MD5) Previous issue date: 2016-02-25 / CNPq / A desertificação é um problema ambiental que atinge várias regiões no mundo, sendo definida como a degradação das terras nas zonas áridas, semiáridas e subúmidas resultante de vários fatores, incluindo variações climáticas e atividades humanas. O objetivo desse estudo foi avaliar o nível de degradação das terras (desertificação) no alto curso da bacia hidrográfica do Rio Paraíba, através da dinâmica temporal e espacial de aspectos climáticos, biofísicos e socioeconômicos. O alto curso da bacia hidrográfica engloba total ou parcialmente, a área de 18 municípios, distribuídos entre as microrregiões do Cariri Ocidental e Oriental do estado da Paraíba. Foram utilizados dados climáticos do período de 1950 a 2013 para as variáveis: precipitação pluvial e índice de aridez (Ia), dados de sensores orbitais - Moderate Resolution Imaging Spectro radiometer (MODIS), período de 2000 a 2013, visando à obtenção do albedo da superfície e do índice de vegetação ajustado ao solo (IVAS) e dados censitários (demográficos e agropecuários) para quantificação do índice socioeconômico e do nível de degradação na região. O teste de Mann-Kendall (MK) foi utilizado para identificação da tendência temporal das variáveis, ao nível de significância de α = 0,05, o método de Sen para quantificação da tendência e a krigagem para análise da dinâmica espacial das variáveis. Os principais resultados evidenciam que há uma tendência crescente da precipitação pluvial e decréscimo da aridez no alto curso da bacia como um todo, durante o período estudado. Pode-se inferir que estas condições não contribuem para desencadear o processo de degradação das terras (desertificação), sugerindo que as causas desse problema ambiental não são climáticas. A precipitação média anual aumenta na direção nordeste-noroeste da bacia, com mínimo (320 mm) em Cabaceiras e máximo (680 mm) nas localidades de Ouro Velho e Prata; o albedo da superfície e o índice de vegetação têm seus valores influenciados pela sazonalidade climática da região. A precipitação pluvial é o elemento que condiciona o aumento do índice de vegetação e diminuição do albedo da superfície, considerando-se que estas duas variáveis têm comportamento inverso. A região central do alto curso da bacia hidrográfica (municípios de Congo, Camalaú e Caraúbas) apresentou baixo índice de vegetação e elevado albedo da superfície, caracterizando possivelmente um processo de degradação das terras. Ao longo do período analisado (2000-2013), estas variáveis apresentaram tendência decrescente, mas não significativa, evidenciando um aumento pouco significativo da degradação das terras. Em relação ao índice socioeconômico geral de cada município – Isem observa-se que sete apresentaram “Moderada” degradação, dez “Baixa” degradação e apenas o município de Boqueirão apresentou situação de “Acentuada” degradação das terras. Os valores médios do Isem por município revelam que está havendo degradação das terras em todo o alto curso da bacia, porém em níveis Moderados e Baixos, sendo a região noroeste a área com maior pressão antrópica. Há uma tendência de aumento do índice socioeconômico - Iseb no alto curso da bacia hidrográfica com valor médio que indica uma situação de degradação “Moderada” das terras. Esse aumento é resultante do crescimento econômico, de programas sociais implantados e das melhorias nas condições de vida da população ao longo dos anos. / Desertification is an environmental problem that affects several regions in the world, defined as the land degradation of arid, semi-arid and sub-humid areas resulting from various factors, including climatic variations and human activities. The aim of this study was to evaluate the level of land degradation (desertification) in the upper course of the watershed of Paraíba River, through the temporal and spatial dynamics of climatic, biophysical and socio-economic aspects. The upper reaches of the watershed encompasses all or part of the area of 18 municipalities, distributed among the micro-regions of Western and Eastern Cariri state of Paraiba. Period of climatic data were used in 1950 the 2013 for the variables: rainfall and aridity index (Ia), orbital data from sensors - MODIS (Moderate Resolution Imaging Spectro radiometer), from 2000 to 2013, to obtain the surface albedo and Vegetation Index adjusted to the ground (SA VI) and census data (population and agricultural) to quantify the socio economic index and the level of degradation in the region. The Mann-Kendall test (MK) was used to identify the time trend variable, the level of significance o f α = 0.05, the Sen method to quantify the trend and Kriging for analyzing spatial dynamics of the variables. The main results show that there is an increasing trend of rainfall and decrease dryness on the upper course of the watershed as a whole, during the period studied. You can infer that these conditions do not contribute to trigger land degradation process (desertification), suggesting that the causes of this environmental problem is not climate. The average annual precipitation increases in the north-northwest direction of the watershed, with minimum (320 mm) in Cabaceiras and maximum (680 mm) in Ouro Velho and Prata localities; the surface albedo and vegetation index have their values influenced by the seasonality of the region. Rainfall is the element that determines the increase in vegetation index and decrease in surface albedo, considering that these two variables have opposite behavior. The central region of the upper course of the watershed (municipalities of Congo, Camalaú and Caraúbas) showe d a low rate of vegetation and high albedo surface, possibly featuring a land degradation process. Throughout the period analyzed (2000-2013), these variables showed a downward trend, but not significant, showing a slight increase of land degradation. Rega rding the general socioeconomic index of each municipality – Isem it is observed that seven had "moderate" degradation ten "Low" degradation and only the municipality of Boqueirão presented situation of "Severe" land degradation. The municipality by Isem average values reveal what's going on land degradation across the upper course of the watershed, but in Moderate and Low levels, and northwest region of the area with increased human pressure. There is a tendency to increase the socioeconomic index - Iseb in the upper course of the watershed with an average value indicating the degradation of situation "moderate" land. This increase is the result of economic growth, implemented social programs and improvements in the living conditions of the population over the years.

Water availability in the ecosystem is one of the most crucial environmental factors that determines global terrestrial biome distribution. However, aridity/humidity conditions in the geologic past are difficult to quantify, mainly owing to the lack of a proper parameter. By using modern global climatic data, we here examine five selected previously proposed aridity indices (AIs), in which the climatic variables involved, including both precipitation and temperature, are simple and likely available in studies of paleoclimatology and paleoecology, although with different degrees of uncertainty. They were first evaluated along the modern climatic zones of eastern China, with the main metric of Thornthwaite humidity index (HI) and with the supplementary reference of soil moisture index (SMI) and near-ground atmospheric relative humidity (RH). Then AIs and the mean annual precipitation (MAP) were further statistically compared with HI, SMI, and RH, respectively, based on 1189 monitored data sets from meteorological stations over the world. The results show that the Köppen aridity index (AIKöppen), expressed as mean annual precipitation divided by mean annual temperature plus a constant of 33, is the most accurate and precise index among all selected indices, supported by the highest correlation coefficient respectively to HI, SMI, and RH, three widely-employed major indicators sensitive to hydrological dynamics in climatology and meteorology. Specifically, AIKöppen does well mirror corresponding HI along four representative transects from North America, South America, Africa, and Australia, which cover the typical arid and humid climates and span the main terrestrial biome types. Moreover, our results also distinctly reveal that, as also shown by many studies on modern climate, precipitation alone is inadequate to measure the hydrological condition, because both temperature and evapotranspiration are two other critical factors that strongly influence water balance in the ecosystem, meanwhile evapotranspiration is mainly affected by temperature. Based on the validated AIKöppen, we briefly discuss the aridity/humidity condition in China during the middle Miocene. The results demonstrate that moisture did decrease westward, but it is also clear that western China in the middle Miocene appears not to have been as dry as previously thought, indicated by the AIKöppen values representing a sub-humid to humid climate.

Water availability in the ecosystem is one of the most crucial environmental factors that determines global terrestrial biome distribution. However, aridity/humidity conditions in the geologic past are difficult to quantify, mainly owing to the lack of a proper parameter. By using modern global climatic data, we here examine five selected previously proposed aridity indices (AIs), in which the climatic variables involved, including both precipitation and temperature, are simple and likely available in studies of paleoclimatology and paleoecology, although with different degrees of uncertainty. They were first evaluated along the modern climatic zones of eastern China, with the main metric of Thornthwaite humidity index (HI) and with the supplementary reference of soil moisture index (SMI) and near-ground atmospheric relative humidity (RH). Then AIs and the mean annual precipitation (MAP) were further statistically compared with HI, SMI, and RH, respectively, based on 1189 monitored data sets from meteorological stations over the world. The results show that the Köppen aridity index (AIKöppen), expressed as mean annual precipitation divided by mean annual temperature plus a constant of 33, is the most accurate and precise index among all selected indices, supported by the highest correlation coefficient respectively to HI, SMI, and RH, three widely-employed major indicators sensitive to hydrological dynamics in climatology and meteorology. Specifically, AIKöppen does well mirror corresponding HI along four representative transects from North America, South America, Africa, and Australia, which cover the typical arid and humid climates and span the main terrestrial biome types. Moreover, our results also distinctly reveal that, as also shown by many studies on modern climate, precipitation alone is inadequate to measure the hydrological condition, because both temperature and evapotranspiration are two other critical factors that strongly influence water balance in the ecosystem, meanwhile evapotranspiration is mainly affected by temperature. Based on the validated AIKöppen, we briefly discuss the aridity/humidity condition in China during the middle Miocene. The results demonstrate that moisture did decrease westward, but it is also clear that western China in the middle Miocene appears not to have been as dry as previously thought, indicated by the AIKöppen values representing a sub-humid to humid climate.

Streams are classified into perennial, intermittent, and ephemeral streams based on flow durations. Perennial stream is the basic network, while intermittent or ephemeral stream is the expanded network. Connection between perennial stream and base flow at the mean annual scale exists since one of the hydrologic functions of perennial stream is to deliver runoff even in low flow seasons. The partitioning of precipitation into runoff and evaporation at the mean annual scale, on the first order, is captured by the ratio of potential evaporation to precipitation (Ep/P called climate aridity index) based on the Budyko hypothesis. The primary focus of this thesis is the relationship between base flow and perennial stream density (Dp) in the Budyko framework. In this thesis, perennial stream density is quantified from the high resolution National Hydrography Dataset for 185 watersheds; the climate control (represented by the climate aridity index) on perennial stream density and on base flow is quantified; and the correlation between base flow and perennial stream density is analyzed. Perennial stream density declines monotonically with the climate aridity index, and an inversely proportional function is proposed to model the relationship between Dp and Ep/P. This monotonic trend of perennial stream density reconciles with the Abrahams curve, and the perennial stream density is only a small portion of the total drainage density. The dependences of base flow ratio (Qb/P) and the normalized perennial stream density on the climate aridity index follow a similar complementary Budyko-type curve. The correlation coefficient between iv the ratio of base flow to precipitation and perennial stream density is found to be 0.74. The similarity between the base flow and perennial stream density reveals the co-evolution between water balance and perennial stream network.