The surface solar radiation(SSR) is of great importance to bio-chemical cycle and life activities.However,it is impossible to observe SSR directly over large areas especially for rugged surfaces such as the Qinghai-Ti...The surface solar radiation(SSR) is of great importance to bio-chemical cycle and life activities.However,it is impossible to observe SSR directly over large areas especially for rugged surfaces such as the Qinghai-Tibet Plateau.This paper presented an improved parameterized model for predicting all-sky global solar radiation on rugged surfaces using Moderate Resolution Imaging Spectroradiometer(MODIS) atmospheric products and Digital Elevation Model(DEM).The global solar radiation was validated using 11 observations within the plateau.The correlation coefficients of daily data vary between 0.67-0.86,while those of the averages of 10-day data are between 0.79-0.97.The model indicates that the attenuation of SSR is mainly caused by cloud under cloudy sky,and terrain is an important factor influencing SSR over rugged surfaces under clear sky.A positive relationship can also be inferred between the SSR and slope.Compared with horizontal surfaces,the south-facing slope receives more radiation,followed by the west-and east-facing slopes with less SSR,and the SSR of the north-facing slope is the least.展开更多
Global warming and the response to it have become a topic of concern in today’s society and are also a research focus in the global scientific community.As the world’s third pole,the global warming amplifier,and the...Global warming and the response to it have become a topic of concern in today’s society and are also a research focus in the global scientific community.As the world’s third pole,the global warming amplifier,and the starting region of China’s climate change,the Qinghai-Tibet Plateau is extremely sensitive to climate change.The permafrost on the Qinghai-Tibet Plateau is rich in natural gas hydrates(NGHs)resources.Under the background of global warming,whether the NGHs will be disassociated and enter the atmosphere as the air temperature rises has become a major concern of both the public and the scientific community.Given this,this study reviewed the trend of global warming and accordingly summarized the characteristics of the temperature increase in the Qinghai-Tibet Plateau.Based on this as well as the distribution characteristics of the NGHs in the permafrost on the Qinghai-Tibet Plateau,this study investigated the changes in the response of the NGHs to global warming,aiming to clarify the impacts of global warming on the NGHs in the permafrost of the plateau.A noticeable response to global warming has been observed in the Qinghai-Tibet Plateau.Over the past decades,the increase in the mean annual air temperature of the plateau was increasingly high and more recently.Specifically,the mean annual air temperature of the plateau changed at a rate of approximately 0.308-0.420℃/10a and increased by approximately 1.54-2.10℃in the past decades.Moreover,the annual mean ground temperature of the shallow permafrost on the plateau increased by approximately 1.155-1.575℃and the permafrost area decreased by approximately 0.34×10^(6)km^(2) from about 1.4×10^(6)km^(2) to 1.06×10^(6)km^(2) in the past decades.As indicated by simulated calculation results,the thickness of the NGH-bearing permafrost on the Qinghai-Tibet Plateau has decreased by 29-39 m in the past 50 years,with the equivalent of(1.69-2.27)×10^(10)-(1.12-1.51)×10^(12)m^(3) of methane(CH_(4))being released due to NGHs dissociation.It is predicted that the thickness of the NGH-bearing permafrost will decrease by 23 m and 27 m,and dissociated and released NGHs will be the equivalent of(1.34-88.8)×10^(10)m^(3) and(1.57-104)×10^(10)m^(3)of CH_(4),respectively by 2030 and 2050.Considering the positive feedback mechanism of NGHs on global warming and the fact that CH_(4) has a higher greenhouse effect than carbon dioxide,the NGHs in the permafrost on the Qinghai-Tibet Plateau will emit more CH_(4) into the atmosphere,which is an important trend of NGHs under the background of global warming.Therefore,the NGHs are destructive as a time bomb and may lead to a waste of efforts that mankind has made in carbon emission reduction and carbon neutrality.Accordingly,this study suggests that human beings should make more efforts to conduct the exploration and exploitation of the NGHs in the permafrost of the Qinghai-Tibet Plateau,accelerate research on the techniques and equipment for NGHs extraction,storage,and transportation,and exploit the permafrost-associated NGHs while thawing them.The purpose is to reduce carbon emissions into the atmosphere and mitigate the atmospheric greenhouse effect,thus contributing to the global goal of peak carbon dioxide emissions and carbon neutrality.展开更多
In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have co...In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have combined modern hydrological conditions with paleoclimate records to explore the mechanism(s)of these changes.This study seeks to improve understanding of hydrological variability on decadal and centennial timescales in the SAYR and to identify its general cause.We first determined annual fluctuations in the surface area of Lake Ngoring from 1985 to 2020 using multi-temporal Landsat images.The results show that lake surface area changes were generally consistent with variations in precipitation,streamflow and the regional dry-wet index in the SAYR,suggesting that the water balance of the Lake Ngoring area is closely associated with regional hydroclimate changes.These records are also comparable to the stalagmite δ^(18)O monsoon record,as well fluctuations in the Southern Oscillation Index(SOI).Moreover,an association of high TSI(total solar insolation)anomalies and sunspot numbers with the expansion of Lake Ngoring surface area is observed,implying that solar activity is the key driving factor for hydrologic variability in the SAYR on a decadal timescale.Following this line of reasoning,we compared the δ^(13)C org-based lake level fluctuations of Lake Ngoring for the last millennium,as previously reported,with the hydroclimatic history and the reconstructed TSI record.We conclude that the hydrological regime of Lake Ngoring has been mainly controlled by centennial fluctuations in precipitation for the last millennium,which is also dominated by solar activity.In general,it appears that solar activity has exerted a dominant influence on the hydrological regime of the SAYR on both decadal and centennial timescales,which is clearly manifested in the variations of lake area and water level of Lake Ngoring.展开更多
基金Under the auspices of Knowledge Innovation Programs of the Chinese Academy of Sciences (No KZCX2-YW-308)National Natural Science Foundation of China (No 40771172, 40901223)
文摘The surface solar radiation(SSR) is of great importance to bio-chemical cycle and life activities.However,it is impossible to observe SSR directly over large areas especially for rugged surfaces such as the Qinghai-Tibet Plateau.This paper presented an improved parameterized model for predicting all-sky global solar radiation on rugged surfaces using Moderate Resolution Imaging Spectroradiometer(MODIS) atmospheric products and Digital Elevation Model(DEM).The global solar radiation was validated using 11 observations within the plateau.The correlation coefficients of daily data vary between 0.67-0.86,while those of the averages of 10-day data are between 0.79-0.97.The model indicates that the attenuation of SSR is mainly caused by cloud under cloudy sky,and terrain is an important factor influencing SSR over rugged surfaces under clear sky.A positive relationship can also be inferred between the SSR and slope.Compared with horizontal surfaces,the south-facing slope receives more radiation,followed by the west-and east-facing slopes with less SSR,and the SSR of the north-facing slope is the least.
基金supported by the projects of the China Geological Survey(DD20190102,DD20221857).
文摘Global warming and the response to it have become a topic of concern in today’s society and are also a research focus in the global scientific community.As the world’s third pole,the global warming amplifier,and the starting region of China’s climate change,the Qinghai-Tibet Plateau is extremely sensitive to climate change.The permafrost on the Qinghai-Tibet Plateau is rich in natural gas hydrates(NGHs)resources.Under the background of global warming,whether the NGHs will be disassociated and enter the atmosphere as the air temperature rises has become a major concern of both the public and the scientific community.Given this,this study reviewed the trend of global warming and accordingly summarized the characteristics of the temperature increase in the Qinghai-Tibet Plateau.Based on this as well as the distribution characteristics of the NGHs in the permafrost on the Qinghai-Tibet Plateau,this study investigated the changes in the response of the NGHs to global warming,aiming to clarify the impacts of global warming on the NGHs in the permafrost of the plateau.A noticeable response to global warming has been observed in the Qinghai-Tibet Plateau.Over the past decades,the increase in the mean annual air temperature of the plateau was increasingly high and more recently.Specifically,the mean annual air temperature of the plateau changed at a rate of approximately 0.308-0.420℃/10a and increased by approximately 1.54-2.10℃in the past decades.Moreover,the annual mean ground temperature of the shallow permafrost on the plateau increased by approximately 1.155-1.575℃and the permafrost area decreased by approximately 0.34×10^(6)km^(2) from about 1.4×10^(6)km^(2) to 1.06×10^(6)km^(2) in the past decades.As indicated by simulated calculation results,the thickness of the NGH-bearing permafrost on the Qinghai-Tibet Plateau has decreased by 29-39 m in the past 50 years,with the equivalent of(1.69-2.27)×10^(10)-(1.12-1.51)×10^(12)m^(3) of methane(CH_(4))being released due to NGHs dissociation.It is predicted that the thickness of the NGH-bearing permafrost will decrease by 23 m and 27 m,and dissociated and released NGHs will be the equivalent of(1.34-88.8)×10^(10)m^(3) and(1.57-104)×10^(10)m^(3)of CH_(4),respectively by 2030 and 2050.Considering the positive feedback mechanism of NGHs on global warming and the fact that CH_(4) has a higher greenhouse effect than carbon dioxide,the NGHs in the permafrost on the Qinghai-Tibet Plateau will emit more CH_(4) into the atmosphere,which is an important trend of NGHs under the background of global warming.Therefore,the NGHs are destructive as a time bomb and may lead to a waste of efforts that mankind has made in carbon emission reduction and carbon neutrality.Accordingly,this study suggests that human beings should make more efforts to conduct the exploration and exploitation of the NGHs in the permafrost of the Qinghai-Tibet Plateau,accelerate research on the techniques and equipment for NGHs extraction,storage,and transportation,and exploit the permafrost-associated NGHs while thawing them.The purpose is to reduce carbon emissions into the atmosphere and mitigate the atmospheric greenhouse effect,thus contributing to the global goal of peak carbon dioxide emissions and carbon neutrality.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171160 and 42172205).
文摘In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have combined modern hydrological conditions with paleoclimate records to explore the mechanism(s)of these changes.This study seeks to improve understanding of hydrological variability on decadal and centennial timescales in the SAYR and to identify its general cause.We first determined annual fluctuations in the surface area of Lake Ngoring from 1985 to 2020 using multi-temporal Landsat images.The results show that lake surface area changes were generally consistent with variations in precipitation,streamflow and the regional dry-wet index in the SAYR,suggesting that the water balance of the Lake Ngoring area is closely associated with regional hydroclimate changes.These records are also comparable to the stalagmite δ^(18)O monsoon record,as well fluctuations in the Southern Oscillation Index(SOI).Moreover,an association of high TSI(total solar insolation)anomalies and sunspot numbers with the expansion of Lake Ngoring surface area is observed,implying that solar activity is the key driving factor for hydrologic variability in the SAYR on a decadal timescale.Following this line of reasoning,we compared the δ^(13)C org-based lake level fluctuations of Lake Ngoring for the last millennium,as previously reported,with the hydroclimatic history and the reconstructed TSI record.We conclude that the hydrological regime of Lake Ngoring has been mainly controlled by centennial fluctuations in precipitation for the last millennium,which is also dominated by solar activity.In general,it appears that solar activity has exerted a dominant influence on the hydrological regime of the SAYR on both decadal and centennial timescales,which is clearly manifested in the variations of lake area and water level of Lake Ngoring.
