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 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 Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest (central Himalaya) in the last 2 decades (1994–2013)

2015 ◽  
Vol 9 (3) ◽  
pp. 1229-1247 ◽  
Author(s):  
F. Salerno ◽  
N. Guyennon ◽  
S. Thakuri ◽  
G. Viviano ◽  
E. Romano ◽  
...  
Keyword(s):  
Time Series ◽  
Monsoon Season ◽  
High Elevation ◽  
Maximum Temperature ◽  
Mountain Range ◽  
Climate Trends ◽  
Monsoon Period ◽  
Temperature And Precipitation ◽  
Recent Climate ◽  
Koshi Basin

Abstract. Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation (> 5000 m a.s.l.). This study specifically explores the southern slopes of Mt. Everest, analyzing the time series of temperature and precipitation reconstructed from seven stations located between 2660 and 5600 m a.s.l. during 1994–2013, complemented with the data from all existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we find that the main and most significant increase in temperature is concentrated outside of the monsoon period. Above 5000 m a.s.l. the increasing trend in the time series of minimum temperature (+0.072 °C yr−1) is much stronger than of maximum temperature (+0.009 °C yr−1), while the mean temperature increased by +0.044 °C yr−1. Moreover, we note a substantial liquid precipitation weakening (−9.3 mm yr−1) during the monsoon season. The annual rate of decrease in precipitation at higher elevations is similar to the one at lower elevations on the southern side of the Koshi Basin, but the drier conditions of this remote environment make the fractional loss much more consistent (−47% during the monsoon period). Our results challenge the assumptions on whether temperature or precipitation is the main driver of recent glacier mass changes in the region. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to a decrease in accumulation (snowfall) than to an increase in surface melting; (2) the melting has only been favoured during winter and spring months and close to the glaciers terminus; (3) a decrease in the probability of snowfall (−10%) has made a significant impact only at glacier ablation zone, but the magnitude of this decrease is distinctly lower than the observed decrease in precipitation; (4) the decrease in accumulation could have caused the observed decrease in glacier flow velocity and the current stagnation of glacier termini, which in turn could have produced more melting under the debris glacier cover, leading to the formation of numerous supraglacial and proglacial lakes that have characterized the region in the last decades.

scholarly journals Multidimensional extremes: joint study of precipitation and temperature time series

2021 ◽  
Author(s):  
Beatrix Izsák ◽  
Tamás Szentimrey ◽  
Mónika Lakatos ◽  
Rita Pongrácz
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Extreme Values ◽  
Standardized Precipitation Index ◽  
Single Element ◽  
Average Temperature ◽  
Temperature And Precipitation ◽  
The Standardized Precipitation Index ◽  
Climatic Time Series ◽  
Precipitation And Temperature

<p>To study climate change, it is essential to analyze extremes as well. The study of extremes can be done on the one hand by examining the time series of extreme climatic events and on the other hand by examining the extremes of climatic time series. In the latter case, if we analyze a single element, the extreme is the maximum or minimum of the given time series. In the present study, we determine the extreme values of climatic time series by examining several meteorological elements together and thus determining the extremes. In general, the main difficulties are connected with the different probability distribution of the variables and the handling of the stochastic connection between them. The first issue can be solved by the standardization procedures, i.e. to transform the variables into standard normal ones. For example, the Standardized Precipitation Index (SPI) uses precipitation sums assuming gamma distribution, or the standardization of temperature series assumes normal distribution. In case of more variables, the problem of stochastic connection can be solved on the basis of the vector norm of the variables defined by their covariance matrix. According to this methodology we have developed a new index in order to examine the precipitation and temperature variables jointly. We present the new index with the mathematical background, furthermore some examples for spatio-temporal examination of these indices using our software MASH (Multiple Analysis of Series for Homogenization; Szentimrey) and MISH (Meteorological Interpolation based on Surface Homogenized Data Basis; Szentimrey, Bihari). For our study, we used the daily average temperature and precipitation time series in Hungary for the period 1870-2020. First of all, our analyses indicate that even though some years may not be considered extreme if only either precipitation or average temperature is taken in to account, but examining the two elements together these years were extreme years indeed. Based on these, therefore, the study of the extremes of multidimensional climate time series complements and thus makes the study of climate change more efficient compared to examining only one-dimensional time series.</p>

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 Supplementary material to "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):  
Surface Area ◽  
Glacier Melting ◽  
Supplementary Material ◽  
Precipitation Trends

scholarly journals Mapping seasonal glacier melt across the Hindu Kush Himalaya with time series SAR

2020 ◽  
Author(s):  
Corey Scher ◽  
Nicholas C. Steiner ◽  
Kyle C. McDonald
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
High Elevation ◽  
Optical Observations ◽  
Eastern Himalaya ◽  
Series Data ◽  
Glacier Surface ◽  
Glacier Melt ◽  
Hindu Kush ◽  
Sar Imagery

Abstract. Current observational data on Hindu Kush Himalayas (HKH) glaciers are sparse and characterizations of seasonal melt dynamics are limited. Time series synthetic aperture radar (SAR) imagery enables detection of reach-scale glacier melt characteristics across continents. We analyze C-band Sentinel-1 A/B SAR time series data, comprised of 32,741 Sentinel-1 A/B SAR images, determine the duration of seasonal glacier melting for 76,831 glaciers (65,108 km2), defined using optical observations, in the HKH across the calendar years 2017–2019. Signals of melt onset and duration are recorded at 90 m spatial resolution and 12-day temporal repeat across 96.62 % (62,907 km2) of the HKH cryosphere. Melt signals persist for more than 40 % of the year at elevations below 4,000 m a.s.l. and in excess of 15 % of each year at elevations exceeding 7,000 m a.s.l. Melt retrievals resemble characteristics of glacio-climatic subregions of the HKH: melt onsets sooner and occurs for a longer portion of each year in the Central and Eastern Himalaya compared to the Western Himalaya and Karakoram regions. Retrievals of seasonal melting span all elevation ranges of significant glacier area in the HKH region, extending greater than 1 km above the maximum elevation of an interpolated 0 ºC summer isotherm. Furthermore, high elevation percolation zones are apparent from meltwater retention indicated by signals of delayed refreeze. Time series SAR datasets are suitable to support operational monitoring of glacier surface melt and the development and assessment of surface energy balance models of melt-driven ablation across the high-elevation temperate global cryosphere.

scholarly journals An Efficient Prediction Model for Water Discharge in Schoharie Creek, NY

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Katerina G. Tsakiri ◽  
Antonios E. Marsellos ◽  
Igor G. Zurbenko
Keyword(s):  
New York ◽  
Time Series ◽  
Water Discharge ◽  
Winter Period ◽  
Statistical Methodology ◽  
Summer Period ◽  
Short Term ◽  
Efficient Prediction ◽  
Climatic Time Series

Flooding normally occurs during periods of excessive precipitation or thawing in the winter period (ice jam). Flooding is typically accompanied by an increase in river discharge. This paper presents a statistical model for the prediction and explanation of the water discharge time series using an example from the Schoharie Creek, New York (one of the principal tributaries of the Mohawk River). It is developed with a view to wider application in similar water basins. In this study a statistical methodology for the decomposition of the time series is used. The Kolmogorov-Zurbenko filter is used for the decomposition of the hydrological and climatic time series into the seasonal and the long and the short term component. We analyze the time series of the water discharge by using a summer and a winter model. The explanation of the water discharge has been improved up to 81%. The results show that as water discharge increases in the long term then the water table replenishes, and in the seasonal term it depletes. In the short term, the groundwater drops during the winter period, and it rises during the summer period. This methodology can be applied for the prediction of the water discharge at multiple sites.

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