全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球...全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球气候模式模拟的针对5种不同因子(加倍二氧化碳、增加2%的太阳辐射、10倍黑碳、5倍硫酸盐、3倍甲烷)高强迫情景下的理想试验,利用气候变化检测和指数专家组(Expert Team on Climate Change Detection and Indices,ETCCDI)定义的4个降水指数,详细分析了不同外部强迫因子作用下全球极端降水的响应.结果表明,相比于平均降水,在5种强迫因子作用下极端降水指数均表现出更大的变化.与加倍二氧化碳相比,增加2%的太阳辐射、5倍硫酸盐气溶胶和3倍甲烷强迫下全球极端降水对温度变化的响应更加强烈,而10倍黑碳气溶胶强迫下的降水变化则表现出较强的模式间差异.在加倍二氧化碳、增加2%的太阳辐射和3倍甲烷强迫下,极端降水的变化表现相似的纬向分布特征,最强的降水响应出现在赤道地区;10倍黑碳、5倍硫酸盐气溶胶强迫下则表现出明显的南北半球差异.水汽收支诊断结果揭示了在高强迫情景下,二氧化碳、太阳辐射和甲烷强迫下热带地区更强烈的降水变化主要与热力作用有关,而动力作用可能是导致黑碳、硫酸盐气溶胶强迫下降水变化的主要原因.展开更多
The Asian summer monsoon(ASM) is a vast climate system, whose variability is critical to the livelihoods of billions of people across the Asian continent. During the past half-century, much progress has been made in u...The Asian summer monsoon(ASM) is a vast climate system, whose variability is critical to the livelihoods of billions of people across the Asian continent. During the past half-century, much progress has been made in understanding variations on a wide range of timescales, yet several significant issues remain unresolved. Of note are two long-standing problems concerning orbital-scale variations of the ASM.(1) Chinese loess magnetic susceptibility records show a persistent glacial-interglacial dominated ~100 kyr(thousand years) periodicity, while the cave oxygen-isotope(δ18 O) records reveal periodicity in an almost pure precession band(~20 kyr periodicity)—the "Chinese 100 kyr problem".(2) ASM records from the Arabian Sea and other oceans surrounding the Asian continent show a significant lag of 8–10 kyr to Northern Hemisphere summer insolation(NHSI), whereas the Asian cave δ18 O records follow NHSI without a significant lag—a discrepancy termed the "sea-land precession-phase paradox". How can we reconcile these differences? Recent and more refined model simulations now provide spatial patterns of rainfall and wind across the precession cycle, revealing distinct regional divergences in the ASM domain, which can well explain a large portion of the disparities between the loess, marine, and cave proxy records. Overall, we also find that the loess, marine, and cave records are indeed complementary rather than incompatible, with each record preferentially describing a certain aspect of ASM dynamics. Our study provides new insight into the understanding of different hydroclimatic proxies and largely reconciles the "Chinese 100 kyr problem" and "sea-land precession-phase paradox".展开更多
The widely accepted“Milankovitch theory”explains insolation-induced waxing and waning of the ice sheets and their effect on the global climate on orbital timescales.In the past half century,however,the theory has of...The widely accepted“Milankovitch theory”explains insolation-induced waxing and waning of the ice sheets and their effect on the global climate on orbital timescales.In the past half century,however,the theory has often come under scrutiny,especially regarding its“100-ka problem.”Another drawback,but the one that has received less attention,is the“monsoon problem,”which pertains to the exclusion of monsoon dynamics in classic Milankovitch theory even though the monsoon prevails over the vast low-latitude(30N to30S)region that covers half of the Earth’s surface and receives the bulk of solar radiation.In this review,we discuss the major issues with the current form of Milankovitch theory and the progress made at the research forefront.展开更多
文摘全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球气候模式模拟的针对5种不同因子(加倍二氧化碳、增加2%的太阳辐射、10倍黑碳、5倍硫酸盐、3倍甲烷)高强迫情景下的理想试验,利用气候变化检测和指数专家组(Expert Team on Climate Change Detection and Indices,ETCCDI)定义的4个降水指数,详细分析了不同外部强迫因子作用下全球极端降水的响应.结果表明,相比于平均降水,在5种强迫因子作用下极端降水指数均表现出更大的变化.与加倍二氧化碳相比,增加2%的太阳辐射、5倍硫酸盐气溶胶和3倍甲烷强迫下全球极端降水对温度变化的响应更加强烈,而10倍黑碳气溶胶强迫下的降水变化则表现出较强的模式间差异.在加倍二氧化碳、增加2%的太阳辐射和3倍甲烷强迫下,极端降水的变化表现相似的纬向分布特征,最强的降水响应出现在赤道地区;10倍黑碳、5倍硫酸盐气溶胶强迫下则表现出明显的南北半球差异.水汽收支诊断结果揭示了在高强迫情景下,二氧化碳、太阳辐射和甲烷强迫下热带地区更强烈的降水变化主要与热力作用有关,而动力作用可能是导致黑碳、硫酸盐气溶胶强迫下降水变化的主要原因.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41888101 & 41731174)。
文摘The Asian summer monsoon(ASM) is a vast climate system, whose variability is critical to the livelihoods of billions of people across the Asian continent. During the past half-century, much progress has been made in understanding variations on a wide range of timescales, yet several significant issues remain unresolved. Of note are two long-standing problems concerning orbital-scale variations of the ASM.(1) Chinese loess magnetic susceptibility records show a persistent glacial-interglacial dominated ~100 kyr(thousand years) periodicity, while the cave oxygen-isotope(δ18 O) records reveal periodicity in an almost pure precession band(~20 kyr periodicity)—the "Chinese 100 kyr problem".(2) ASM records from the Arabian Sea and other oceans surrounding the Asian continent show a significant lag of 8–10 kyr to Northern Hemisphere summer insolation(NHSI), whereas the Asian cave δ18 O records follow NHSI without a significant lag—a discrepancy termed the "sea-land precession-phase paradox". How can we reconcile these differences? Recent and more refined model simulations now provide spatial patterns of rainfall and wind across the precession cycle, revealing distinct regional divergences in the ASM domain, which can well explain a large portion of the disparities between the loess, marine, and cave proxy records. Overall, we also find that the loess, marine, and cave records are indeed complementary rather than incompatible, with each record preferentially describing a certain aspect of ASM dynamics. Our study provides new insight into the understanding of different hydroclimatic proxies and largely reconciles the "Chinese 100 kyr problem" and "sea-land precession-phase paradox".
基金supported by the NationalNatural Science Foundation ofChina(41888101 and 42150710534).
文摘The widely accepted“Milankovitch theory”explains insolation-induced waxing and waning of the ice sheets and their effect on the global climate on orbital timescales.In the past half century,however,the theory has often come under scrutiny,especially regarding its“100-ka problem.”Another drawback,but the one that has received less attention,is the“monsoon problem,”which pertains to the exclusion of monsoon dynamics in classic Milankovitch theory even though the monsoon prevails over the vast low-latitude(30N to30S)region that covers half of the Earth’s surface and receives the bulk of solar radiation.In this review,we discuss the major issues with the current form of Milankovitch theory and the progress made at the research forefront.
