Glacier area change (1993-2019) and its relationship to debris cover, proglacial lakes, and morphological parameters in the Chandra-Bhaga Basin, Western Himalaya, India

Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years 1993,2000,2010,and 2019 using Landsat Thematic Mapper(TM),Enhanced Thematic Mapper(ETM),and Operational Land Imager(OLI)datasets.A total of 251 glaciers,each having an area above 0.5 km^(2),were identified,which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods:1993-2000,2000-2010,and 2010-2019.The total glacierized area was 996±62 km^(2) in 1993,which decreased to 973±70 km^(2) in 2019.The mean rate of glacier area loss was higher in the recent decade(2010-2019),at 0.036 km^(2),compared to previous decades(0.029 km^(2) in 2000-2010 and 0.025 km^(2) in 1993-2000).Supraglacial debris cover changes are also mapped over the period of 1993 and 2019.It is found that the supraglacial debris cover increased by 14.12±2.54 km^(2)(15.2%)during 1993-2019.Extensive field surveys on Chhota Shigri,Panchi II,Patsio,Hamtah,Mulkila,and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets.Controls of various morphological parameters on retreat were also analyzed.It is observed that small,clean ice,south oriented glaciers,and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin.

Impact of climate change and human activities on the spatiotemporal dynamics of surface water area in Gansu Province, China

Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with complex terrain and variable climate,as the research subject.Based on Google Earth Engine,we used Landsat data and the Open-surface Water Detection Method with Enhanced Impurity Control method to monitor the spatiotemporal dynamics of surface water area in Gansu Province from 1985 to 2022,and quantitatively analyzed the main causes of regional differences in surface water area.The findings revealed that surface water area in Gansu Province expanded by 406.88 km2 from 1985 to 2022.Seasonal surface water area exhibited significant fluctuations,while permanent surface water area showed a steady increase.Notably,terrestrial water storage exhibited a trend of first decreasing and then increasing,correlated with the dynamics of surface water area.Climate change and human activities jointly affected surface hydrological processes,with the impact of climate change being slightly higher than that of human activities.Spatially,climate change affected the'source'of surface water to a greater extent,while human activities tended to affect the'destination'of surface water.Challenges of surface water resources faced by inland arid and semi-arid areas like Gansu Province are multifaceted.Therefore,we summarized the surface hydrology patterns typical in inland arid and semi-arid areas and tailored surface water'supply-demand'balance strategies.The study not only sheds light on the dynamics of surface water area in Gansu Province,but also offers valuable insights for ecological protection and surface water resource management in inland arid and semi-arid areas facing water scarcity.

Can We Manage Coastal Area? Will We?——The Institutional Change of the Coastal Area Management of Taiwan

The Coastal Zone Management Act was finally promulgated in 2015,while Ministry of the Interior was asked to draft a coastal management act in 1991 by Executive Yuan.It was until the government’s lifting of martial law in 1987,vigorous activities started prevailing on coastal areas.And relevant legal documents were on sea reclamation for development in the 1980’s by Council of Agriculture.The approval of“Taiwan Coastal Area Natural Environment Protection Plan”showed an era of environmental protection in 1980s.However,it was surely not market driven,similar to land development,but some efforts by the administration systems.Through all the years,the efforts were put on drafting plans and these efforts were not quite sounding.The coastal disasters and further climate change caught the attention of relevant NGOs,scholars,politicians,and the society.At the critical juncture the government was made to react to outside demands.And then the Coastal Zone Management Act was passed by Legislative Yuan,establishing an integrated coastal management system in Taiwan.As such,it is proposed to look into this long process of the attempt with the concept of institutional change in order to understand this coastal environmental preservation and protection issue in a broader scope.

Reactive Transport Process of Earthquake-induced Hydrochemical Changes in Guanding Thermal Spring,Western Sichuan,China

Earthquake-related hydrochemical changes in thermal springs have been widely observed;however,quantitative modeling of the reactive transport process is absent.In the present study,we apply reactive transport simulation to capture the hydrochemical responses in a thermal spring following the Wenchuan Ms 8.0 and Lushan Ms 7.0 earthquakes.We first constrain deep reservoir geothermal fluid compositions and temperature by multicomponent geothermometry,and then a reactive geochemical transport model is constructed to reproduce the hydrochemical evolution process.The results show that the recharge from the shallow aquifer increases gradually until it reaches a peak because of the permeability enhancement caused by the Lushan earthquake,which may be the mechanism to explain the earthquake-related hydrochemical responses.In contrast to the postseismic effect of the Wenchuan earthquake,the chemical evolution can be considered as hydrochemical anomalies related to the Lushan earthquake.This study proves that the efficient simulation of reactive transport processes is useful for investigating earthquake-related signals in hydrochemical time series.

Spatiotemporal changes of gross primary productivity and its response to drought in the Mongolian Plateau under climate change

Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.

Spatio-Temporal Changes in the Rice Planting Area and Their Relationship to Climate Change in Northeast China: A Model-Based Analysis

Rice is one of the most important grain crops in Northeast China （NEC） and its cultivation is sensitive to climate change. This study aimed to explore the spatio-temporal changes in the NEC rice planting area over the period of 1980-2010 and to analyze their relationship to climate change. To do so, the CLUE-S （conversion of land use and its effects at small region extent） model was ifrst updated and used to simulate dynamic changes in the rice planting area in NEC to understand spatio-temporal change trends during three periods： 1980-1990, 1990-2000 and 2000-2010. The changing results in individual periods were then linked to climatic variables to investigate the climatic drivers of these changes. Results showed that the NEC rice planting area expanded quickly and increased by nearly 4.5 times during 1980-2010. The concentration of newly planted rice areas in NEC constantly moved northward and the changes were strongly dependent on latitude. This conifrmed that climate change, increases in temperature in particular, greatly inlfuenced the shift in the rice planting area. The shift in the north limit of the NEC rice planting area generally followed a 1＆#176;C isoline migration pattern, but with an obvious time-lag effect. These ifndings can help policy makers and crop producers take proper adaptation measures even when exposed to the global warming situation in NEC.

Do farmers care about climate change? Evidence from five major grain producing areas of China

Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in China.The results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation changes.Specifically,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation change.Therefore,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.

Vegetation changes in the agricultural-pastoral areas of northern China from 2001 to 2013

Climate change and human activity have resulted in increasing change of vegetation growth globally. Numerous studies have been conducted on extreme climate events and analyses of ecological environment evolution. However, such studies have placed little emphasis on vegetation change and spatial variation in this type of ecotone. Accordingly, this study analyzed the changes in vegetation type and growth using the 16-d composite MOD13A1 product with 1-km resolution and MOD12Q1 product with 1-km resolution. We used the mean, maximum, standard deviation normalized-difference vegetation index（NDVI） values, and the rate of change（ROC） of NDVI value to explain vegetation changes within the studied ecotone. Our results showed that significant vegetation type and growth changes have occurred in the study area. From 2001 to 2013, for example, with the exception of 2001, 2004 and 2009, a certain extent of grassland area was converted to cropland. Drought severity index（DSI） results indicate that there exists drought in 2001, 2004 and 2009. Such temporal changes in cropland and grassland area confirmed the ecological vulnerability of the ecotone. At the same time, vegetation varied spatially from west to east and from south to north. The mean, maximum and standard deviation NDVI values were all sorted in descending order based on differences in latitude and longitude, as follows： NDVI_（2013）〉NDVI_（2009）〉NDVI_（2004）〉NDVI_（2001）

Lake Area Changes and the main causes in the hinterland of Badain Jaran Desert during 1973–2010,China

Lake area information in the Badain Jaran Desert in 1973, 1990, 2000, and 2010 was obtained by visual interpretation and water index analysis of remote sensing images, based on the spatial and temporal characteristics of lake area changes during 37 years. Results indicated that the nttmber of lakes declined from 94 to 82 and the total surface area was reduced by 3.69 km2 during 1973-2010. The desert lake area reduced by different degrees in different periods, but this occurred most rapidly during 1973-1990. According to the statistics of lake area changes, lake area decreases mainly occurred in the lakes with areas less than 0.2 km2, while the areas of lakes greater than 0.9 km2 only fluctuated. The changes of lake areas were probably due to changes in the quantity of underground water supplies rather than the effects of local climate change or human factors.

Changes in cultivated land patterns and driving forces in the Three Gorges Reservoir area, China, from 1992 to 2015

Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultivated land in the head,central, and tail areas of the reservoir that took place between 1992 and 2015;we then studied the spatial distribution of the cultivated land in the three parts of the reservoir;finally, we studied the driving forces behind the changes in the cultivated land. The results derived are as follows.(1) During the construction of the Three Gorges Project(TGP, 1992–2015), the area of cultivated land around the reservoir decreased by30.23 million ha. This reduction occurred in phases:the most severe change in cultivated land occurred during the later stage of the project(2002–2010);only 0.62 million ha of cultivated land did not change between 1992 and 2015.(2) Spatial pattern analysis showed that the cultivated land in the three parts of the reservoir changed from a northern distribution to a southern distribution;thus, the area of cultivated land in the north decreased over the time period. The area of cultivated land in the head and tail areas decreased by varying degrees, while it increased in the central area over the 23 years, indicating that the change in cultivated land showed regional differences.(3) The TGP, the policy of reverting farmland to forest,and urbanization were the main driving factors for the change of cultivated land, but there were differences in their impacts at different stages.(4) According to the patch dynamics of the land cover change, the degree of change gradually intensified during the early and later stages of the project and then stabilized during the operational period. Our research provides scientific support for the protection of cultivated land resources and food security in the reservoir area and for the coordination of social and economic development, which is of great significance to sustainable development in the reservoir area.

Inter-provincial Differences in Rice Multi-cropping Changes in Main Double-cropping Rice Area in China: Evidence from Provinces and Households

Since the early 1980 s, the multi-cropping index for rice has decreased significantly in main double-cropping rice area in China, which is the primary double-cropping rice(DCR) production area. This decline may bring challenges to food security in China because rice is the staple food for more than 60% of the Chinese population. It has been generally recognized that rapidly rising labor costs due to economic growth and urbanization in China is the key driving force of the ‘double-to-single' rice cropping system adaption. However, not all provinces have shown a dramatic decline in DCR area, and labor costs alone cannot explain this difference. To elucidate the reasons for these inter-provincial distinctions and the dynamics of rice cropping system adaption, we evaluated the influencing factors using provincial panel data from 1980 to 2015. We also used household survey data for empirical analysis to explore the mechanisms driving differences in rice multi-cropping changes. Our results indicated that the eight provinces in the study can be divided into three spatial groups based on the extent of DCR area decline, the rapidly-declining marginal, core, and stable zones. Increasing labor cost due to rapid urbanization was the key driving force of rice cropping system adaption, but the land use dynamic vary hugely among different provinces. These differences between zones were due to the interaction between labor price and accumulated temperature conditions. Therefore, increasing labor costs had the greatest impact in Zhejiang, Anhui, and Hubei, where the accumulated temperature is relatively low and rice multi-cropping index declined dramaticly. However, labor costs had little impact in Guangdong and Guangxi. Differences in accumulated temperature conditions resulted in spatially different labor demands and pressure on households during the busy season. As a result, there have been different profits and rice multi-cropping changes between provinces and zones. Because of these spatial differences, regionally appropriate policies that provide appropriate subsidies for early rice in rapidly-declining marginal zone such as Zhejiang and Hubei should be implemented. In addition, agricultural mechanization and the number of agricultural workers have facilitated double-cropping; therefore, small machinery and agricultural infrastructure construction should be further supported.

THE WET-DRY CHANGES IN RECENT 40YEARS IN TAKLIMAKAN AREA

Using the precipitation data in recent 40 years of 48 meteorological stations in Taklimakan area and neighboring areas, this paper analyzes the stage and periodicity of the wet-dry changes in a year and four seasons. The paper also compares the correlativity of precipitation between Taklimakan area and around Mountains, and obtained some statisticconclusions as follows. (1) The precipitation changes of a year and four seasons in Taklimakan area have different wet-dryperiods and change periodicities. (2) Summer precipitation has well directive sense to annual precipitation in Taklimakanarea with a correlation coefficient 0. 901, and the negative correlation between precipitation and temperature in summer isvery remarkable. (3) There is definite correlation between annual precipitation in Taklimakan area and position of polarvortex. When longitude of polar vortex is partial west in February and its latitude is partial north in September of the lastyear, annual precipitation is above its mean in the area. In addition, it is beneficial to obtain more summer precipitation inthe area when position of polar vortex is partial west in February.

The spatial-temporal changes of the land use/cover in the Dongting Lake area during the last decade

The research on the land use/cover change is one of the frontiers and the hot spots in the global change research. Based on the Chinese resource and environment spatial-temporal database, and using the Landsat TM and ETM data of 1990 and 2000 respectively, we analyzed the spatial-temporal characteristics of land use/cover changes in the Dongting Lake area during the last decade. The result shows that during the last ten years there were three land-use types that had changed remarkably. The cultivated land decreased by 0.57% of the total cultivated land. The built-up land and water area expanded, with an increase of 8.97% and 0.43% respectively. The conversion between land use types mostly happened among these three land-use types, especially frequently between cultivated land and water area. The land-use change speed of land-use type is different. Three cities experienced the greatest degree of land-use change among all the administrative districts, which means that the land use in these cities changed much quickly. The following changed area was the west and south of the Dongting Lake area. The slowest changed area is the north and east area.

Satellite monitoring of land-use and land-cover changes in northern Togo protected areas

Remote-sensing data for protected areas in northern Togo, obtained in three different years （2007, 2000, and 1987）, were used to assess and map changes in land cover and land use for this drought prone zone. The normalized difference vegetation index （NDVI） was applied to the images to map changes in vegetation. An unsupervised classification, followed by classes recoding, filtering, identifications, area computing and post-classification process were applied to the composite of the three years of NDVI images. Maximum likelihood classification was applied to the 2007 image （ETM＋2007） using a supervised classification process. Seven vegetation classes were defined from training data sets. The seven classes included the following biomes： riparian forest, dry forest, flooded vegetation, wooded savanna, fallows, parkland, and water. For these classes, the overall accuracy and the overall kappa statistic for the classi- fied map were 72.5% and 0.67, respectively. Data analyses indicated a great change in land resources; especially between 1987 and 2000 proba- bly due to the impact of democratization process social, economic, and political disorder from 1990. Wide-scale loss of vegetation occurred during this period. However, areas of vegetation clearing and regrowth were more visible between 2000 and 2007. The main source of confusion in the contingency matrix was due to heterogeneity within certain classes. It could also be due to spectral homogeneity among the classes. This research provides a baseline for future ecological landscape research and for the next management program in the area.

Mapping of moraine dammed glacial lakes and assessment of their areal changes in the central and eastern Himalayas using satellite data

The relatively rapid recession of glaciers in the Himalayas and formation of moraine dammed glacial lakes(MDGLs) in the recent past have increased the risk of glacier lake outburst floods(GLOF) in the countries of Nepal and Bhutan and in the mountainous territory of Sikkim in India. As a product of climate change and global warming, such a risk has not only raised the level of threats to the habitation and infrastructure of the region, but has also contributed to the worsening of the balance of the unique ecosystem that exists in this domain that sustains several of the highest mountain peaks of the world. This study attempts to present an up to date mapping of the MDGLs in the central and eastern Himalayan regions using remote sensing data, with an objective to analyse their surface area variations with time from 1990 through 2015, disaggregated over six episodes. The study also includes the evaluation for susceptibility of MDGLs to GLOF with the least criteria decision analysis(LCDA). Forty two major MDGLs, each having a lake surface area greater than 0.2 km2, that were identified in the Himalayan ranges of Nepal, Bhutan, and Sikkim, have been categorized according to their surface area expansion rates in space and time. The lakes have been identified as located within the elevation range of 3800 m and6800 m above mean sea level(a msl). With a total surface area of 37.9 km2, these MDGLs as a whole were observed to have expanded by an astonishing 43.6% in area over the 25 year period of this study. A factor is introduced to numerically sort the lakes in terms of their relative yearly expansion rates, based on their interpretation of their surface area extents from satellite imageries. Verification of predicted GLOF events in the past using this factor with the limited field data as reported in literature indicates that the present analysis may be considered a sufficiently reliable and rapid technique for assessing the potential bursting susceptibility of the MDGLs. The analysis also indicates that, as of now, there are eight MDGLs in the region which appear to be in highly vulnerable states and have high chances in causing potential GLOF events anytime in the recent future.

Variation Characteristics of Hydrothermal Resources Effectiveness Under the Background of Climate Change in Southern Rice Production Area of China

The spatiotemporal characteristics of hydrothermal resources in southern rice production area of China have changed under the background of climate change,and this change would affect the effectiveness of hydrothermal resources during local rice growing period.According to the cropping system subdivision in southern rice production area of China during 1980s,this study used climate data from 254 meteorological stations and phonological data from 168 agricultural observation stations in the south of China,and adopted 6 international evaluation indices about the effectiveness of hydrothermal resources to analyze the temporal and spatial characteristics of hydrothermal resources during the growing period of single cropping rice system and double cropping rice system for 16 planting zones in the whole study area.The results showed that：in southern rice production area of China,the effectiveness of thermal resources of single cropping rice area（SCRA） was less than that of double cropping rice area（DCRA）,whereas the effectiveness of thermal resources of both SARA and DCRA showed a decreasing trend.The index value of effective precipitation satisfaction of SCRA was higher than that of DCRA,nevertheless the index value of effective precipitation satisfaction of both SCRA and DCRA showed a decreasing trend.There was a significant linear relationship between effective thermal resource and water demand,likely water demand increased by 18 mm with every 100°C d increase of effective heat.Effective precipitation satisfaction index（EPSI） showed a negative correlation with effective heat,yet showed a positive correlation with effective precipitation.EPSI reduced by 1% when effective heat resource increased by 125°C d.This study could provide insights for policy makers,land managers or farmers to improve water and heat resource uses and rationally arrange rice production activities under global climate change condition.

Analysis to driving forces of land use change in Lu’an mining area

By selecting impact factors of driving force and formulating evaluation criteria of the impacts, the evaluation system of corresponding driving force impact of land use change was established. Taking Lu'an mining area as an example, the specific impact factors of coal mine were comprehensively evaluated and analyzed in order to carry out qualitative and quantitative analysis for the driving force of mining-land use change. The principal component analysis shows that the social and economic development in mining area from 2000 to 2007 demonstrates continuous accelerate trends, and the impacts of its overall driving force to land use change are increased gradually. The socio-economic factors have more impacts to mining-land use change than those of the natural resources. The main driving force of mining-land use change also include population, technological progress and policy.

Re-assessing Vegetation Carbon Storage and Emissions from Land Use Change in China Using Surface Area

Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and calculated terrestrial vegetation carbon storage(VCS) for 2000 and 2015 using land surface area and traditional ellipsoid area. The land surface area is estimated by a triangular network on the high precision digital elevation model.The results showed that: 1) The VCS estimated by the surface area measurement in 2000 and 2015 were 0.676 and0.692 Pg C(1 Pg = 1015 g) higher than the VCS calculated using the ellipsoid area, respectively. 2) As the elevation increases, the differences between VCS estimated by surface area measurement and ellipsoid area measurement are expanding. Specially, a clear gap was present starting from an elevation of 500 m, with the relative error exceeds8.99%. 3) The total amount of carbon emitted due to land use change reached 0.114 Pg C. The conversions of forestland and grassland to other land use type are the main reasons of the loss of vegetation carbon storage, resulting in a total amount of biomass carbon storage decreased by 0.942 and 0.111 Pg C, respectively. This study was a preliminary exploration of incorporating land surface area as a factor in resource estimation, which can help more accurately understand the status of resources and the environment in the region.

Distribution Prediction of Suitable Growth Area for Eucommia ulmoides in China under Climatic Change Background

[ Objective] The research aimed to study distribution prediction of suitable growth area for Eucommia ulmoides in China under climatic change background. [ Method] By using the maximum entropy model and many kinds of climate change scenarios, we predicted current and future distribution pattems of suitable growth area for Eucommia ulmoides in China and its change process. [ Result ] At present, highly suitable growth area of E. ulmoides mainly distributed in Sichuan, Shaanxi and Chongqing, Under climate change background, total suitable growth areas in future three decades all drastically reduced when compared with that at present. It was noteworthy that moderately and highly suitable growth areas of wild E. ulmoides all disappeared, and junction between Shaanxi and Gansu and Taibai Mountain would be stable suitable growth area of wild E. ulmoides. [ Condusioa] The research could provide useful reference data for investigation, protection and sustainable development of the wild E. ulmoides resources.

Analysis of the Influencing Factors of Changes in Foxtail Millet Planting Area in Hebei Province

Since reform and open to the outside world,foxtail millet planting area in Hebei Province has constantly reduced,and its planting region has changed from the whole province into some regions,with obvious changes. In this paper,by using qualitative and quantitative approaches like chart analysis,summarizing,Delphi method and osculating value model,the influencing factors of changes in millet growing region in Hebei Province were studied. The results showed that the changes of millet planting area were closely related to many factors,such as little investment in scientific research,weak policy support,a single consumer product demand,the rapid development of other staple crops, labor migration,relatively low comparative effectiveness and physiological characteristics of the millet itself. Then some suggestions were put forward,such as increasing research support,strengthening scientific research strength,researching and developing deeply processed products, expanding consumer groups,improving millet policy support,providing subsidies for planting the improved varieties,researching and developing various types of machinery,and increasing millet production technology training.