应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球...应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球形的雪粒,球形雪粒的积雪反照率更低;吸光性颗粒物对光谱反照率的影响主要在可见光和紫外波段。此外,雪粒径的增大能使吸光性颗粒物的光吸收效应增强。结合东北地区的实测数据,我们发现SAMDS模拟的积雪宽波段反照率与实测结果较为一致。同时,SAMDS模式模拟结果表明,在东北地区,积雪中0. 1～1μg·g^(-1)的黑碳浓度导致积雪宽波段反照率减少2%～8%,造成的瞬时辐射强迫为9～35 W·m^(-2)。展开更多
Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate;however,their potential effects on the cryosphere are difficult to assess.Catastrophic wildfires in Aus...Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate;however,their potential effects on the cryosphere are difficult to assess.Catastrophic wildfires in Australia during 2019–2020 emitted large amounts of light-absorbing particles(LAPs)to the atmosphere.Satellite observations indicate that these LAPs caused unprecedented snow-darkening of glaciers in New Zealand through long-range transport and deposition,with their effects lasting for up to three months in January–March 2020,influencing>90%of total glacier/snow and leading to a mean broadband snow-reflectance reduction of 0.08±0.03.This snow darkening accelerated snowmelt by~0.41±0.2 cm day–1 during the southern summer,equivalent to that caused by a~1.8°C increase in air temperature.This indicates the significant impact of the 2019–2020 Australian wildfires on the hydrologic cycle in New Zealand,exceeding that of the local climate warming of~1.5°C since the preindustrial period.Wildfire-induced snow darkening is not limited to New Zealand.Future projections of wildfire incidence indicate widespread effects of snow darkening on the global cryosphere.展开更多
文摘应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球形的雪粒,球形雪粒的积雪反照率更低;吸光性颗粒物对光谱反照率的影响主要在可见光和紫外波段。此外,雪粒径的增大能使吸光性颗粒物的光吸收效应增强。结合东北地区的实测数据,我们发现SAMDS模拟的积雪宽波段反照率与实测结果较为一致。同时,SAMDS模式模拟结果表明,在东北地区,积雪中0. 1～1μg·g^(-1)的黑碳浓度导致积雪宽波段反照率减少2%～8%,造成的瞬时辐射强迫为9～35 W·m^(-2)。
基金This research was supported by the National Science Fund for Distinguished Young Scholars(42025102)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(41521004)the National Natural Science Foundation of China(42075061 and 41975157).
文摘Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate;however,their potential effects on the cryosphere are difficult to assess.Catastrophic wildfires in Australia during 2019–2020 emitted large amounts of light-absorbing particles(LAPs)to the atmosphere.Satellite observations indicate that these LAPs caused unprecedented snow-darkening of glaciers in New Zealand through long-range transport and deposition,with their effects lasting for up to three months in January–March 2020,influencing>90%of total glacier/snow and leading to a mean broadband snow-reflectance reduction of 0.08±0.03.This snow darkening accelerated snowmelt by~0.41±0.2 cm day–1 during the southern summer,equivalent to that caused by a~1.8°C increase in air temperature.This indicates the significant impact of the 2019–2020 Australian wildfires on the hydrologic cycle in New Zealand,exceeding that of the local climate warming of~1.5°C since the preindustrial period.Wildfire-induced snow darkening is not limited to New Zealand.Future projections of wildfire incidence indicate widespread effects of snow darkening on the global cryosphere.
