This dissertation uses multiple tools to investigate tropical anvil, i.e., thick, non-precipitating cloud associated with deep convection with the main objectives to provide a climatology of tropics-wide anvil properties and a better understanding of anvil formation, and to provide a more realistic assessment of the radiative impact of tropical anvil on the large-scale circulation. Based on 10 years (1998-2007) of observations, anvil observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation (PR) shows significant geographical variations, which can be linked to variations in the parent convection. Strong upper level wind shear appears to assist the generation of anvil and may further explain the different anvil statistics over land and ocean. Variations in the large-scale environment appear to play a more important role in anvil production in regions where convection regularly attains heights greater than 7 km. For regions where convection is less deep, variations in the depth of the convection and the large-scale environment likely contribute more equally to anvil generation. Anvil radiative heating profiles are estimated by extrapolating millimeter cloud radar (MMCR) radiative properties from Manus to the 10-year TRMM PR record. When the unconditional anvil areal coverage is taken into account, the anvil radiative heating becomes quite weak, increasing the PR latent heating profile by less than 1 percent at mid and upper levels. Stratiform rain and cirrus radiative heating contributions increase the upper level latent heating by 12 percent. This tropical radiative heating only slightly enhances the latent heating driven model response throughout the tropics, but more significantly over the East Pacific. These modest circulation changes suggest that previous studies may have overemphasized the importance of radiative heating in terms of Walker and Hadley circulation variations. Further, the relationship of cloud radiative heating to latent heating needs to be taken into account for more realistic studies of cloud radiative forcing on the large-scale circulation.

Two mechanisms appear to be primarily responsible for the formation of cirrus clouds in Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. Here we propose to identify TTL cirrus clouds by analyzing water content measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Aura Microwave Limb Sounder (MLS). Using ice water content (IWC) and water vapor (H2O) abundances we identify TTL cirrus clouds that contain too much ice to have been formed in situ — and therefore must be of convective origin. We use two methods to infer amounts of water vapor available for in situ formation. Clouds with IWC greater than this threshold are categorized as being of convective origin; clouds with IWC below the threshold are ambiguous — they could either form from in situ or still be of convective origin. Applying the thresholds from December 2008 to November 2009, we found that at least 19.2% of tropical cirrus were definitively of convective origin at the tropopause (375 K) during boreal winter. At each level, we found three maxima in the occurrence of convective cirrus: western Pacific, equatorial Africa, and South America. Averaged over the entire tropics (30oS to 30oN), we found convective cirrus occurs more frequently in boreal winter and less frequently in boreal summer, basically following the a decreasing trend from DJF, MAM, SON, to JJA. During boreal summer, we found that only 4.6% of tropical cirrus come from convection. Sensitivity tests show that the thresholds derived at 390 K have the largest uncertainty. At lower levels, especially 375 K, our thresholds are robust.

Thanks to Taiwan¡¦s geographic advantage of being located in subtropics, tropical fruits in Taiwan have high quality. There is never shortage of variously fresh and high-quality fruits in four seasons of a year in Taiwan, which should have gained Taiwan competitive advantages in international markets and should have made Taiwan nominated to be a standard for international markets. However, a large number of problems and difficulties in production and marketing system of the fruit industry have caused tropical fruits in Taiwan unable to get into foreign markets. The prospect of this research is to find out the influential marketing factors by carefully examining export and other related difficulties; consequently, the purpose of this research is to find out the most effective solutions among a large number of marketing factors to help the fruit industry in Taiwan out of difficulties. The research methods used in this study are interviewing fruit production and marketing professionals to analyze the fruit export difficulties, assisted with marketing 4P and STP structure, brand thesis, and real case studies. With the above mentioned methods, I structurally analyze difficulties and problems. According to the findings of this research, tropical fruits in Taiwan evidently have powerful competitive advantages; however, the ¡§Product¡¨ aspect of 4P is still the major factor that should be solved at first when tropical fruits in Taiwan confront export competition. All of the followings, fruit classification, production capacity management, packing, freezing, inspection, brand and the other related factors, are the main problems mentioned consistently by professionals. This research also finds that ¡§brand¡¨ makes industry, government, schools reach one accord; therefore, it should be taken as our long-term developmental direction and the best strategy to resuscitate Taiwan¡¦s fruits in international markets. Nevertheless, as it is shown on the related documents, Council of Agriculture¡¦s brand identification system is nothing more than just providing a name to a species of fruit, which is unable to build up its fame to domestic consumers and much less to foreign markets. According to the above findings of this research, four suggestions are proposed as follows: 1. Establishment of national brand series: to take advantage of Taiwan¡¦s great fame, using its name to sell our tropical fruits, and to take rural towns¡¦ or Co-operatives¡¦ brand as the sub-brand or the extensive brand. 2. Brand clock: to promote and cross sell fruits in different seasons based on different fruit periods. To construct brand life span with brand clock by taking national brand as the principal axis and assisted with season fruits¡¦ production periods; as a result, Taiwan¡¦s fruits can be sufficiently provided to export markets all the year around, keeping out from unstable supply that Taiwan has confronted for a long time. 3. Market Segmentation and Positioning: tropical fruits enjoy the advantage of freshness and numerous species, but they are difficult to keep fresh. Although freezing technology has been improved a lot, keeping tropical fruits fresh during a long distance transportation is always a real challenge. Consequently, choosing a proper market to do marketing according to the feature of every kind of fruit is highly recommended. This will avoid fruit quality from declining caused by blindly selling all fruits to uncompetitive markets or caused by a long distance transportation. Both of the above situations will cause a negative impact on brand. 4. Fruit identification: to take fruits that agricultural units can easily promote as the major products, to enhance production, to abandon uncompetitive species of fruits, to effectively manage and control fruit cultivating technology (Intelligent property right and species control), and to promote fruit identification system. All of the above methods will help Taiwan¡¦s fruit industry have their competition in the market.

This study evaluates the simulation of tropical precipitation by the Community Climate Model, Version 3, developed at the National Center for Atmospheric Research. For an evaluation of the annual cycle of precipitation, monthly-mean precipitation rates from an ensemble of CCM3 simulations are compared to those computed from observations of the TRMM satellite over a 44-month period. On regional and sub-regional scales, the comparison fares well over much of the Eastern Hemisphere south of 10◦S and over South America. However, model - satellite differences are large in portions of Central America and the Caribbean, the southern tropical Atlantic, the northern Indian Ocean, and the western equatorial and southern tropical Pacific. Since precipitation in the Tropics is the primary source of latent energy to the general circulation, such large model - satellite differences imply large differences in the amount of latent energy released. Differences are seasonally-dependent north of 10◦N, where model wet biases occur in realistic wet seasons or model-generated artificial wet seasons. South of 10◦N, the model wet biases exist throughout the year or have no recognizable pattern. For an evaluation of the diurnal cycle of precipitation, hourly-averaged precipitation rates from the same ensemble of simulations and for the same 44-month period are compared to observations from the Tropical Rainfall Measuring Mission (TRMM) satellite. Comparisons are made for 15◦ longitude ?? 10◦ latitude boxes and for larger geographical areas within the Tropics. The temporally- and spatially-averaged hourly precipitation rates from CCM3 and from TRMM are fit to the diurnal harmonic by the method of linear leastsquares regression, and the phases and the amplitudes of the diurnal cycles are compared. The model??s diurnal cycle is too strong over major land masses, particularly over South America (by a factor of 3), and is too weak over many oceans, particularly the northwestern Tropical Pacific (by a factor of 2). The model-satellite phase differences tend to be more homogeneous. The peak in the daily precipitation in the model consistently precedes the observations nearly everywhere. Phase differences are large over Australia, Papua New Guinea, and Saharan Africa, where CCM3 leads TRMM by 4 hours, 5 to 6 hours, and 9 to 11 hours respectively. A model sensitivity experiment shows that increasing the convective adjustment time scale in the model??s deep convective parameterization reduces its positive amplitude bias over land regions but has no effect on the phase of the diurnal cycle.

Over the past century, glaciers throughout the tropics have predominately retreated. These small glaciers, which respond quickly to climate changes, are becoming increasingly important in understanding glacier-climate interactions. The glaciers on Mt. Jaya in Irian Jaya, Indonesia are the last remaining tropical glaciers in the Western Pacific region. Although considerable research exists investigating the climatic factors most affecting tropical glacier mass balance, extensive research on the Mt. Jaya glaciers has been lacking since the early 1970s. Using IKONOS satellite images, the ice extents of the Mt. Jaya glaciers in 2000, 2002, 2003, 2004, and 2005 were mapped. The mapping indicates that the recessional trend which began in the mid-19th century has continued. Between 1972 (Allison, 1974; Allison and Peterson, 1976) and 2000, the glaciers lost approximately 67.6% of their area, representing a reduction in surface ice area from 7.2 km2 to 2.35 km2. From 2000 to 2005, the glaciers lost an additional 0.54 km2, representing approximately 24% of the 2000 area. Rates of ice loss, calculated from area measurements for the Mt. Jaya glaciers in 1942, 1972, 1987, and 2005, indicate that ice loss on Mt. Jaya has increased during each subsequent period. Preliminary modeling, using 600 hPa atmospheric temperature, specific humidity, wind speeds, surface precipitation, and radiation values, acquired from the NCEP Reanalysis dataset, indicates that the only climate variable having a statistically-significant change with a magnitude great enough to strongly affect ice loss on these glaciers was an increase in the mean monthly atmospheric temperature of 0.24°C between 1972 and 1987. However, accelerated ice loss occurring from 1988-2005 without large observed changes in the weather variables indicates that a more complex explanation may be required. Small, though statistically-significant changes were found in regional precipitation, with precipitation decreasing from 1972-1987 and increasing from 1988-2005. While, individually, these changes were not of sufficient magnitude to have greatly affected ice loss on these glaciers, increased precipitation along with a rising freezing level may have resulted in a greater proportion of the glacier surface being affected by rain. This may account for the increased recession rate observed in the latter period.

Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2004. / Thesis advisor(s): Patrick A. Harr, Russell L. Elsberry. Includes bibliographical references (p. 117-118). Also available online.

This study takes a spatial perspective to analyze traditional land-use and production systems in humid tropical environments, with emphasis on the agricultural dimension. The setting is the Pastaza River Basin in the Ecuadorian Amazon and the Achuar and Shiwiar indigenous groups are used to highlight the elements of these systems. This dissertation relies on land use/land cover change and agricultural change theories to analyze indigenous land use systems. The study uses empirical data to examine the linkages between decision making, the demand for land resources, and landscape change. Results suggest that the transition from nomadic-dispersed to permanent-nucleic villages leads to the implementation of a land-use zoning system that responds to changes in resource availability. This system can be represented by a concentric land-use-zones model that depicts an efficient distribution of land resources around service infrastructure such as landing strips, health centers, or schools. Overall, the demand for land resources varies with changes in household composition. At the beginning of the household’s life cycle, the demand for farmed land is relatively low because the family’s food requirements are minimal. As households grow, the demand increases and agriculture expands. As young adults leave the house for any reason, the demand for cultivated land decreases and the extent of agricultural land use contracts. In addition, the demand for land resources is associated with ecological conditions of the habitats in which production occurs and with distance to the community. Areas with good soils have smaller agricultural plots than areas with poor soils. People living in poor-soil environments manage larger fields but produce less food per unit of area than households with good soils. The probability of an area of becoming agriculture increases in sites farther away from existing cultivation fields, service infrastructure, and homes since areas closer to these features have already been used and are recuperating as fallows. Additionally, people are cultivating in areas that are relatively steeper than older agricultural fields. These findings suggest that indigenous people are expanding agriculture into areas with adverse pedologic and topographic conditions, which may be an indication of overall scarcity of land resources for food production. / text

We defined a new type of open Gromov-Witten invariants on hyperK\"aher manifolds with holomorphic / Mathematics

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This document proposes an objective technique to estimate the intensity and predict the formation of tropical cyclones using infrared satellite imagery. As the tropical cyclone develops from an unstructured cloud cluster and intensifies the cloud structures become more axisymmetric around an identified reference point or center. This methodology processes the image gradient to measure the level of symmetry of cloud structures, which characterizes the degree of cloud organization of the tropical cyclone.The center of a cloud system is calculated by projecting and accumulating parallel lines to the gradient vectors. The point where the highest number of line intersections is located pinpoints a common point where the corresponding gradients are directed. This location is used as the center of the system. Next, a procedure that characterizes the departure of the weather system structure from axisymmetry is implemented. The deviation angle of each gradient vector relative to a radial line projected from the center is calculated. The variance of the set of deviation angles enclosed by a circular area around the center describes the axisymmetry of the system, and its behavior through time depicts its dynamics. Results are presented that show the time series of the deviation angle variances is well correlated with the National Hurricane Center best-track estimates.The formation of tropical cyclones is detected by extending the deviation-angle variance technique, it is calculated using every pixel in the scene as the center of the cloud system. Low angle variances indicate structures with high levels of axisimmetry, and these values are compared to a set of thresholds to determine whether a cloud structure can be considered as a vortex. The first detection in a sequence indicates a nascent storm. It was found that 86% of the tropical cyclones during 2004 and 2005 were detected 27 h on average before the National Hurricane Center classified them as tropical storms (33kt).Finally, two procedures to locate the center of a tropical cyclone are compared to the National Hurricane Center best-track center database. Results show that both techniques provide similar accuracy, which increases as the tropical cyclone evolves.