scholarly journals Glacier melting and precipitation trends detected by surface area changes in Himalayan ponds

2016 ◽  
Vol 10 (4) ◽  
pp. 1433-1448 ◽  
Author(s):  
Franco Salerno ◽  
Sudeep Thakuri ◽  
Nicolas Guyennon ◽  
Gaetano Viviano ◽  
Gianni Tartari
Keyword(s):  
Surface Area ◽  
Landsat Imagery ◽  
High Elevation ◽  
Maximum Temperature ◽  
Study Region ◽  
Glacier Shrinkage ◽  
Glacier Melt ◽  
Glacier Melting ◽  
Glacier Ice ◽  
Climatic Time Series

Abstract. Climatic time series for high-elevation Himalayan regions are decidedly scarce. Although glacier shrinkage is now sufficiently well described, the changes in precipitation and temperature at these elevations are less clear. This contribution shows that the surface area variations of unconnected glacial ponds, i.e. ponds not directly connected to glacier ice, but that may have a glacier located in their hydrological basin, can be considered as suitable proxies for detecting past changes in the main hydrological components of the water balance. On the south side of Mt Everest, glacier melt and precipitation have been found to be the main drivers of unconnected pond surface area changes (detected mainly with Landsat imagery). In general, unconnected ponds have decreased significantly by approximately 10 ± 5 % in terms of surface area over the last 50 years (1963–2013 period) in the study region. Here, an increase in precipitation occurred until the mid-1990s followed by a decrease until recent years. Until the 1990s, glacier melt was constant. An increase occurred in the early 2000s, while a declining trend in maximum temperature has caused a reduction in the glacier melt during recent years.

scholarly journals Glacier melting and precipitation trends detected by surface area changes in Himalayan ponds

2016 ◽  
Author(s):  
Franco Salerno ◽  
Sudeep Thakuri ◽  
Nicolas Guyennon ◽  
Gaetano Viviano ◽  
Gianni Tartari
Keyword(s):  
Time Series ◽  
Surface Area ◽  
High Elevation ◽  
Maximum Temperature ◽  
Glacier Shrinkage ◽  
Glacier Melt ◽  
Glacier Melting ◽  
Climatic Time Series ◽  
Precipitation And Temperature ◽  
Precipitation Trends

Abstract. Climatic time series for high-elevation Himalayan regions are decidedly scarce. Although glacier shrinkage is now sufficiently well described, the changes in precipitation and temperature at these elevations are less clear. This contribution shows that the surface area variations of unconnected glacial ponds, i.e., ponds not directly connected to glaciers, can be considered suitable proxies for detecting changes in the main hydrological components of the water balance on the south side of Mt. Everest. Glacier melt and precipitation trends have been inferred by analyzing the surface area variations of ponds with various degrees of glacial coverage within the basin. In general, unconnected ponds over the last fifty years (1963–2013 period) have decreased significantly by approximately 10 %. We inferred an increase in precipitation occurred until the mid-1990s followed by a decrease until recent years. Until the 1990s, glacier melt was constant. An increase occurred in the early 2000s, and in the recent years, contrasting the observed glacier reduction, a declining trend in maximum temperature has decreased the glacier melt.

scholarly journals A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery

2019 ◽  
Vol 11 (24) ◽  
pp. 2955 ◽  
Author(s):  
Roberto O. Chávez ◽  
Duncan A. Christie ◽  
Matías Olea ◽  
Talia G. Anderson
Keyword(s):  
Landsat Imagery ◽  
High Elevation ◽  
Management Policy ◽  
Future Research ◽  
Regional Patterns ◽  
Unique Type ◽  
Study Region ◽  
The Sustainable Development ◽  
Productivity Dynamics ◽  
Productivity Assessment

The high Andean peatlands, locally known as “bofedales”, are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has provided critical water and forage resources for the livestock of the indigenous Aymara communities for thousands of years. Nevertheless, little is known about the productivity dynamics of the high Andean peatlands, particularly in the drier western Altiplano region bordering the Atacama desert. Here, we provide the first digital peatland inventory and multiscale productivity assessment for the entire western Altiplano (63,705 km2) using 31 years of Landsat data (about 9000 scenes) and a non-parametric approach for estimating phenological metrics. We identified 5665 peatland units, covering an area of 510 km2, and evaluated the spatiotemporal productivity patterns at the regional, peatland polygon, and individual pixel scales. The regional assessment shows that the peatland areas and peatlands with higher productivity are concentrated towards the northern part of our study region, which is consistent with the Altiplano north–south aridity gradient. Regional patterns further reveal that the last seven years (2011–2017) have been the most productive period over the past three decades. While individual pixels show contrasting patterns of reductions and gains in local productivity during the most recent time period, most of the study area has experienced increases in annual productivity, supporting the regional results. Our novel database can be used not only to explore future research questions related to the social, biological, and hydrological influences on peatland productivity patterns, but also to provide technical support for the sustainable development of livestock practices and conservation and water management policy in the Altiplano region.

scholarly journals Temporal and Spatial Characteristics of Precipitation and Temperature in Punjab, Pakistan

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1916 ◽  
Author(s):  
Nawaz ◽  
Li ◽  
Chen ◽  
Guo ◽  
Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Climatic Variability ◽  
Regional Scale ◽  
Elevation Gradient ◽  
High Elevation ◽  
Maximum Temperature ◽  
Moderate Increase ◽  
Study Region ◽  
Lower Elevation ◽  
Precipitation And Temperature

Identifying the changes in precipitation and temperature at a regional scale is of great importance for the quantification of climate change. This research investigates the changes in precipitation and surface air temperature indices in the seven irrigation zones of Punjab Province during the last 50 years; this province is a very important region in Pakistan in terms of agriculture and irrigated farming. The reliability of the data was examined using double mass curve and autocorrelation analysis. The magnitude and significance of the precipitation and temperature were visualized by various statistical methods. The stations’ trends were spatially distributed to better understand climatic variability across the elevation gradient of the study region. The results showed a significant warming trend in annual Tmin (minimum temperature) and Tmean (mean temperature) in different irrigation zones. However, Tmax (maximum temperature) had insignificant variations except in the high elevation Thal zone. Moreover, the rate of Tmin increased faster than that of Tmax, resulting in a reduction in the diurnal temperature range (DTR). On a seasonal scale, warming was more pronounced during spring, followed by that in winter and autumn. However, the summer season exhibited insignificant negative trends in most of the zones and gauges, except in the higher-altitude Thal zone. Overall, Bahawalpur and Faisalabad are the zones most vulnerable to warming annually and in the spring, respectively. Furthermore, the elevation-dependent trend (EDT) indicated larger increments in Tmax for higher-elevation (above 500 m a.s.l.) stations, compared to the lower-elevation ones, on both annual and seasonal scales. In contrast, the Tmin showed opposite trends at higher- and lower-elevation stations, while a moderate increase was witnessed in Tmean trends from lower to higher altitude over the study region. An increasing trend in DTR was observed at higher elevation, while a decreasing trend was noticed at the lower-elevation stations. The analysis of precipitation data indicated wide variability over the entire region during the study period. Most previous studies reported no change or a decreasing trend in precipitation in this region. Conversely, our findings indicated the cumulative increase in annual and autumn precipitation amounts at zonal and regional level. However, EDT analysis identified the decrease in precipitation amounts at higher elevation (above 1000 m a.s.l.) and increase at the lower-elevation stations. Overall, our findings revealed unprecedented evidence of regional climate change from the perspectives of seasonal warming and variations in precipitation and temperature extremes (Tmax and Tmin) particularly at higher-elevation sites, resulting in a variability of the DTR, which could have a significant influence on water resources and on the phenology of vegetation and crops at zonal and station level in Punjab.

scholarly journals Tropical glacier meltwater contribution to stream discharge: a case study in the Cordillera Blanca, Peru

2003 ◽  
Vol 49 (165) ◽  
pp. 271-281 ◽  
Author(s):  
Bryan G. Mark ◽  
Geoffrey O. Seltzer
Keyword(s):  
Stream Flow ◽  
Cordillera Blanca ◽  
Stream Discharge ◽  
Glacier Meltwater ◽  
Glacier Melt ◽  
The Pacific ◽  
Glacier Melting ◽  
Glacier Ice ◽  
Stream Geochemistry ◽  
Annual Discharge

AbstractDischarge measurements, climate observations and hydrochemical samples gathered monthly (1998/99) in the Yanamarey and Uruashraju glacier-fed catchments of the Cordillera Blanca, Peru, permit an analysis of the glacier meltwater contribution to stream-flow. These glacier catchments feed the Río Santa, which discharges into the Pacific Ocean. Based on a water-balance computation, glacier melt contributes an estimated 35% of the average discharge from the catchments. For comparison, a volumetric end-member mixing model of oxygen isotopes shows glacier melt contributes 30–45% to the total annual discharge. Based on stream geochemistry, discharge from the Yanamarey glacier catchment provides 30% of the annual volume discharged from the Querococha watershed, which is <10% glacierized. By analogy, the larger Río Santa watershed, also <10% glacierized, receives at least 12% of its annual discharge from melting glacier ice. Tributary watersheds to the Río Santa with larger fractions of glacier cover have less variable runoff and enhanced discharge, demonstrating that the glaciers effectively buffer stream discharge seasonally. With continued glacier melting, stream-flow will likely become more variable, and there will be less dry-season runoff.

scholarly journals Strong controls of daily minimum temperature on the autumn photosynthetic phenology of subtropical vegetation in China

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peixin Ren ◽  
Zelin Liu ◽  
Xiaolu Zhou ◽  
Changhui Peng ◽  
Jingfeng Xiao ◽  
...  
Keyword(s):  
Climate Change ◽  
Minimum Temperature ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Time Lag ◽  
Evergreen Forest ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Study Region ◽  
Cumulative Precipitation

Abstract Background Vegetation phenology research has largely focused on temperate deciduous forests, thus limiting our understanding of the response of evergreen vegetation to climate change in tropical and subtropical regions. Results Using satellite solar-induced chlorophyll fluorescence (SIF) and MODIS enhanced vegetation index (EVI) data, we applied two methods to evaluate temporal and spatial patterns of the end of the growing season (EGS) in subtropical vegetation in China, and analyze the dependence of EGS on preseason maximum and minimum temperatures as well as cumulative precipitation. Our results indicated that the averaged EGS derived from the SIF and EVI based on the two methods (dynamic threshold method and derivative method) was later than that derived from gross primary productivity (GPP) based on the eddy covariance technique, and the time-lag for EGSsif and EGSevi was approximately 2 weeks and 4 weeks, respectively. We found that EGS was positively correlated with preseason minimum temperature and cumulative precipitation (accounting for more than 73% and 62% of the study areas, respectively), but negatively correlated with preseason maximum temperature (accounting for more than 59% of the study areas). In addition, EGS was more sensitive to the changes in the preseason minimum temperature than to other climatic factors, and an increase in the preseason minimum temperature significantly delayed the EGS in evergreen forests, shrub and grassland. Conclusions Our results indicated that the SIF outperformed traditional vegetation indices in capturing the autumn photosynthetic phenology of evergreen forest in the subtropical region of China. We found that minimum temperature plays a significant role in determining autumn photosynthetic phenology in the study region. These findings contribute to improving our understanding of the response of the EGS to climate change in subtropical vegetation of China, and provide a new perspective for accurately evaluating the role played by evergreen vegetation in the regional carbon budget.

scholarly journals Climate Extremes over the Arabian Peninsula Using RegCM4 for Present Conditions Forced by Several CMIP5 Models

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 675 ◽  
Author(s):  
Almazroui
Keyword(s):  
Land Surface ◽  
Arabian Peninsula ◽  
Climate Model ◽  
Regional Climate ◽  
Coupled Model ◽  
Climate Extremes ◽  
Maximum Temperature ◽  
Cmip5 Models ◽  
Study Region ◽  
Temperature And Precipitation

This paper investigates the temperature and precipitation extremes over the Arabian Peninsula using data from the regional climate model RegCM4 forced by three Coupled Model Intercomparison Project Phase 5 (CMIP5) models and ERA–Interim reanalysis data. Indices of extremes are calculated using daily temperature and precipitation data at 27 meteorological stations located across Saudi Arabia in line with the suggested procedure from the Expert Team on Climate Change Detection and Indices (ETCCDI) for the present climate (1986–2005) using 1981–2000 as the reference period. The results show that RegCM4 accurately captures the main features of temperature extremes found in surface observations. The results also show that RegCM4 with the CLM land–surface scheme performs better in the simulation of precipitation and minimum temperature, while the BATS scheme is better than CLM in simulating maximum temperature. Among the three CMIP5 models, the two best performing models are found to accurately reproduce the observations in calculating the extreme indices, while the other is not so successful. The reason for the good performance by these two models is that they successfully capture the circulation patterns and the humidity fields, which in turn influence the temperature and precipitation patterns that determine the extremes over the study region.

scholarly journals Assessing Field-Specific Risk of Soybean Sudden Death Syndrome Using Satellite Imagery in Iowa

2016 ◽  
Vol 106 (8) ◽  
pp. 842-853 ◽  
Author(s):  
S. Yang ◽  
X. Li ◽  
C. Chen ◽  
P. Kyveryga ◽  
X. B. Yang
Keyword(s):  
High Risk ◽  
Sudden Death ◽  
Satellite Imagery ◽  
Vegetation Index ◽  
Landsat Imagery ◽  
Quantitative Polymerase Chain Reaction ◽  
Sudden Death Syndrome ◽  
Maximum Temperature ◽  
Clear Trend ◽  
Specific Risk

Moderate resolution imaging spectroradiometer (MODIS) satellite imagery from 2004 to 2013 were used to assess the field-specific risks of soybean sudden death syndrome (SDS) caused by Fusarium virguliforme in Iowa. Fields with a high frequency of significant decrease (>10%) of the normalized difference vegetation index (NDVI) observed in late July to middle August on historical imagery were hypothetically considered as high SDS risk. These high-risk fields had higher slopes and shorter distances to flowlines, e.g., creeks and drainages, particularly in the Des Moines lobe. Field data in 2014 showed a significantly higher SDS level in the high-risk fields than fields selected without considering NDVI information. On average, low-risk fields had 10 times lower F. virguliforme soil density, determined by quantitative polymerase chain reaction, compared with other surveyed fields. Ordinal logistic regression identified positive correlations between SDS and slope, June NDVI, and May maximum temperature, but high June maximum temperature hindered SDS. A modeled SDS risk map showed a clear trend of potential disease occurrences across Iowa. Landsat imagery was analyzed similarly, to discuss the ability to utilize higher spatial resolution data. The results demonstrated the great potential of both MODIS and Landsat imagery for SDS field-specific risk assessment.

scholarly journals Small glaciers disappearing in the tropical Andes: a case-study in Bolivia: Glaciar Chacaltaya (16o S)

2001 ◽  
Vol 47 (157) ◽  
pp. 187-194 ◽  
Author(s):  
Edson Ramírez ◽  
Bernard Francou ◽  
Pierre Ribstein ◽  
Marc Descloitres ◽  
Roger Guérin ◽  
...  
Keyword(s):  
Surface Area ◽  
Hydrological Regime ◽  
High Elevation ◽  
Climatic Conditions ◽  
Ice Age ◽  
Tropical Andes ◽  
Equilibrium Line Altitude ◽  
La Paz ◽  
Ground Penetrating ◽  
Near Future

AbstractGlaciar Chacaltaya is an easily accessible glacier located close to La Paz, Bolivia. Since 1991, information has been collected about the evolution of this glacier since the Little Ice Age, with a focus on the last six decades. The data considered in this study are monthly mass-balance measurements, yearly mappings of the surface topography and a map of the glacier bed given by ground-penetrating radar survey. A drastic shrinkage of ice has been observed since the early 1980s, with a mean deficit about 1 m a−1 w.e. From 1992 to 1998, the glacier lost 40% of its average thickness and two-thirds of its total volume, and the surface area was reduced by >40%. With a mean estimated equilibrium-line altitude lying above its upper reach, the glacier has been continuously exposed to a dominant ablation on the whole surface area. If the recent climatic conditions continue, a complete extinction of this glacier in the next 15 years can be expected. Glaciar Chacaltaya is representative of the glaciers of the Bolivian eastern cordilleras, 80% of which are small glaciers (<0.5 km2). A probable extinction of these glaciers in the near future could seriously affect the hydrological regime and the water resources of the high-elevation basins.

scholarly journals Glacier changes in the Pascua-Lama region, Chilean Andes (29° S): recent mass balance and 50 yr surface area variations

2011 ◽  
Vol 5 (4) ◽  
pp. 1029-1041 ◽  
Author(s):  
A. Rabatel ◽  
H. Castebrunet ◽  
V. Favier ◽  
L. Nicholson ◽  
C. Kinnard
Keyword(s):  
Mass Balance ◽  
Surface Area ◽  
Monitoring Program ◽  
High Elevation ◽  
Aerial Photographs ◽  
Late 20Th Century ◽  
Surface Mass ◽  
Glacier Changes ◽  
Chilean Andes

Abstract. Since 2003, a monitoring program has been conducted on several glaciers and glacierets in the Pascua-Lama region of the Chilean Andes (29° S/70° W; 5000 m a.s.l.), permitting the study of glaciological processes on ice bodies in a subtropical, arid, high-elevation area where no measurements were previously available. In this paper we present: (1) six years of glaciological surface mass balance measurements from four ice bodies in the area, including a discussion of the nature of the studied glaciers and glacierets and characterization of the importance of winter mass balance to annual mass balance variability; and (2) changes in surface area of twenty ice bodies in the region since 1955, reconstructed from aerial photographs and satellite images, which shows that the total glaciated surface area reduced by ~29% between 1955 and 2007, and that the rate of surface area shrinkage increased in the late 20th century. Based on these datasets we present a first interpretation of glacier changes in relation with climatic parameters at both local and regional scales.

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