Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term...Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term high-quality observations over Peruvian glaciers has motivated the extensive use of reanalysis data to describe the climatic evolution of these glaciers.However,the representativeness and uncertainties of these reanalysis products over these glaciers are still poorly constrained.This study evaluates the ability of the ERA-Land reanalysis(ERAL)to reproduce hourly and monthly 2 m air temperature and relative humidity(T2m and Rh2m,respectively)over several Peruvian glaciers.We compared the ERAL with data from four on-glacier automatic weather stations(AWS),whose hourly time series were completed with nearby stations,for the period January 2017 to December 2019.Results indicates a better performance of the reanalysis for T2m(r>0.80)than for Rh2m(~0.4<r<~0.6)in all four glaciers.Concerning the observations,both parameters show a daily cycle influenced by the presence of the glacier.This influence is more prominent during the dry months when the so-called glacier damping and cooling effects are stronger.On a monthly time scale,the ERAL validation for both parameters are better in wet outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m)rather than in dry outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m).Among all sites considered in the study,the Rh2m bias is the highest in the Cavalca glacier(correlation of 0.81;RMSE 13%,MAE 11% and bias 8.3%)and the lowest in Artesonraju glacier(correlation of 0.96;RMSE 3%;MAE 2.3% and bias-0.8%).Based on certain considerations outlined in this paper,it is appropriate to use ERAL to characterize T2m and Rh2m conditions on Peruvian glaciers,particularly in the wet outer tropics.展开更多
The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"...The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"S;77°25’02"W)and associated processes were documented employing multi-proxy approach including the analysis of remotely sensed images(1948-2016),the Schmidt hammer rock test and lichenometric dating.It is shown that Churup glacier has lost the vast majority of its estimated LIA extent(1.05±0.1 km^2;45.0×10^6-57.4×10^6 m^3).The rate of glacier retreat is documented to vary in space(SE,SW and NW-facing slopes)and time,with the peak between 1986 and 1995.With an area of 0.045 km^2 in 2016,it is expected that the complete deglaciation of the Churup valley is inevitable in the near future.Recently(post-LIA)exposed bedrock surfaces have shown higher R-values(54.2-66.4,AVG 63.3,STDEV 2.9)compared to pre-LIA exposed surfaces(46.1-59.3,AVG 50.1,STDEV 4.9),confirming the links to the duration of rock weathering.The Lichenometric dating is applied to recently exposed areas and elevations above 4800 m a.s.l.,revealing only limited reliability and agreement with the age of deglaciation estimated from remotely-sensed images in such an environment.展开更多
Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat...Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat series images, a digital elevation model from SRTM, and previously published data were used. Estimated total glacier area in 1988, 1993, 1997 and 2004 was 3.85 km2±0.13 km2, 3.01 km2±0.08 km2, 2.49 km2±0.07 km2 and 1.725 km2 ±0.042 km2, respectively. Only 0.58 km2±0.016 km2 glacierized area remained in 2015 in Puncak Jaya, which is about 84.9% loss in just 27 years. If this rate continued, the remaining tropical glaciers in Australasia would disappear in the 2020 s. Timeseries analysis of climate variables showed significant positive trends in air temperature(0.009°C per year) and relative humidity(0.43% per year) but no considerable tendency was observed for precipitation. Warming climate together with mining activities would accelerate loss of glacier coverage in this region.展开更多
基金funded by the Ministry of Science and Innovation of Spain through the research project(PID2020-113247RA-C22)by the National Fund for Scientific and Technological Development of Peru trough the PERMAFROST ENSO research project(081-2021)。
文摘Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term high-quality observations over Peruvian glaciers has motivated the extensive use of reanalysis data to describe the climatic evolution of these glaciers.However,the representativeness and uncertainties of these reanalysis products over these glaciers are still poorly constrained.This study evaluates the ability of the ERA-Land reanalysis(ERAL)to reproduce hourly and monthly 2 m air temperature and relative humidity(T2m and Rh2m,respectively)over several Peruvian glaciers.We compared the ERAL with data from four on-glacier automatic weather stations(AWS),whose hourly time series were completed with nearby stations,for the period January 2017 to December 2019.Results indicates a better performance of the reanalysis for T2m(r>0.80)than for Rh2m(~0.4<r<~0.6)in all four glaciers.Concerning the observations,both parameters show a daily cycle influenced by the presence of the glacier.This influence is more prominent during the dry months when the so-called glacier damping and cooling effects are stronger.On a monthly time scale,the ERAL validation for both parameters are better in wet outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m)rather than in dry outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m).Among all sites considered in the study,the Rh2m bias is the highest in the Cavalca glacier(correlation of 0.81;RMSE 13%,MAE 11% and bias 8.3%)and the lowest in Artesonraju glacier(correlation of 0.96;RMSE 3%;MAE 2.3% and bias-0.8%).Based on certain considerations outlined in this paper,it is appropriate to use ERAL to characterize T2m and Rh2m conditions on Peruvian glaciers,particularly in the wet outer tropics.
基金the Ministry of Education, Youth and Sports of the Czech Republic within the framework of the National Sustainability Programme Ⅰ(NPU Ⅰ), Grant No. LO1415
文摘The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"S;77°25’02"W)and associated processes were documented employing multi-proxy approach including the analysis of remotely sensed images(1948-2016),the Schmidt hammer rock test and lichenometric dating.It is shown that Churup glacier has lost the vast majority of its estimated LIA extent(1.05±0.1 km^2;45.0×10^6-57.4×10^6 m^3).The rate of glacier retreat is documented to vary in space(SE,SW and NW-facing slopes)and time,with the peak between 1986 and 1995.With an area of 0.045 km^2 in 2016,it is expected that the complete deglaciation of the Churup valley is inevitable in the near future.Recently(post-LIA)exposed bedrock surfaces have shown higher R-values(54.2-66.4,AVG 63.3,STDEV 2.9)compared to pre-LIA exposed surfaces(46.1-59.3,AVG 50.1,STDEV 4.9),confirming the links to the duration of rock weathering.The Lichenometric dating is applied to recently exposed areas and elevations above 4800 m a.s.l.,revealing only limited reliability and agreement with the age of deglaciation estimated from remotely-sensed images in such an environment.
基金Ton Duc Thang University, Ho Chi Minh City, Vietnam, for research support
文摘Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat series images, a digital elevation model from SRTM, and previously published data were used. Estimated total glacier area in 1988, 1993, 1997 and 2004 was 3.85 km2±0.13 km2, 3.01 km2±0.08 km2, 2.49 km2±0.07 km2 and 1.725 km2 ±0.042 km2, respectively. Only 0.58 km2±0.016 km2 glacierized area remained in 2015 in Puncak Jaya, which is about 84.9% loss in just 27 years. If this rate continued, the remaining tropical glaciers in Australasia would disappear in the 2020 s. Timeseries analysis of climate variables showed significant positive trends in air temperature(0.009°C per year) and relative humidity(0.43% per year) but no considerable tendency was observed for precipitation. Warming climate together with mining activities would accelerate loss of glacier coverage in this region.
