scholarly journals The evolution of sub-monsoon systems in the Afro-Asian monsoon region during the Holocene– comparison of different transient climate model simulations

2015 ◽  
Vol 11 (2) ◽  
pp. 305-326 ◽  
Author(s):  
A. Dallmeyer ◽  
M. Claussen ◽  
N. Fischer ◽  
K. Haberkorn ◽  
S. Wagner ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Climate Model ◽  
East Asian Monsoon ◽  
East Asian ◽  
Precipitation Trend ◽  
Monsoon Region ◽  
North African ◽  
Asian Monsoon Region ◽  
The Holocene ◽  
Climate Model Simulations

Abstract. The recently proposed global monsoon hypothesis interprets monsoon systems as part of one global-scale atmospheric overturning circulation, implying a connection between the regional monsoon systems and an in-phase behaviour of all northern hemispheric monsoons on annual timescales (Trenberth et al., 2000). Whether this concept can be applied to past climates and variability on longer timescales is still under debate, because the monsoon systems exhibit different regional characteristics such as different seasonality (i.e. onset, peak and withdrawal). To investigate the interconnection of different monsoon systems during the pre-industrial Holocene, five transient global climate model simulations have been analysed with respect to the rainfall trend and variability in different sub-domains of the Afro-Asian monsoon region. Our analysis suggests that on millennial timescales with varying orbital forcing, the monsoons do not behave as a tightly connected global system. According to the models, the Indian and North African monsoons are coupled, showing similar rainfall trend and moderate correlation in centennial rainfall variability in all models. The East Asian monsoon changes independently during the Holocene. The dissimilarities in the seasonality of the monsoon sub-systems lead to a stronger response of the North African and Indian monsoon systems to the Holocene insolation forcing than of the East Asian monsoon and affect the seasonal distribution of Holocene rainfall variations. Within the Indian and North African monsoon domain, precipitation solely changes during the summer months, showing a decreasing Holocene precipitation trend. In the East Asian monsoon region, the precipitation signal is determined by an increasing precipitation trend during spring and a decreasing precipitation change during summer, partly balancing each other. A synthesis of reconstructions and the model results do not reveal an impact of the different seasonality on the timing of the Holocene rainfall optimum in the different sub-monsoon systems. Rather they indicate locally inhomogeneous rainfall changes and show that single palaeo-records should not be used to characterise the rainfall change and monsoon evolution for entire monsoon sub-systems.

scholarly journals The evolution of sub-monsoon systems in the Afro-Asian monsoon region during the Holocene – comparison of different transient climate model simulations

2014 ◽  
Vol 10 (3) ◽  
pp. 2293-2353 ◽  
Author(s):  
A. Dallmeyer ◽  
M. Claussen ◽  
N. Fischer ◽  
K. Haberkorn ◽  
S. Wagner ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Climate Model ◽  
East Asian Monsoon ◽  
East Asian ◽  
Precipitation Trend ◽  
Monsoon Region ◽  
North African ◽  
Asian Monsoon Region ◽  
The Holocene ◽  
Climate Model Simulations

Abstract. The recently proposed global monsoon hypothesis interprets monsoon systems as part of one global-scale atmospheric overturning circulation, implying a connection between the regional monsoon systems and an in-phase behaviour of all northern hemispheric monsoons on annual timescales (Trenberth et al., 2000). Whether this concept can be applied to past climates and variability on longer timescales is still under debate, because the monsoon systems exhibit different regional characteristics such as different seasonality (i.e. onset, peak, and withdrawal). To investigate the interconnection of different monsoon systems during the pre-industrial Holocene, five transient global climate model simulations have been analysed with respect to the rainfall trend and variability in different sub-domains of the Afro-Asian monsoon region. Our analysis suggests that on millennial timescales with varying orbital forcing, the monsoons do not behave as a tightly connected global system. According to the models, the Indian and North African monsoons are coupled, showing similar rainfall trend and moderate correlation in rainfall variability in all models. The East Asian monsoon changes independently during the Holocene. The dissimilarities in the seasonality of the monsoon sub-systems lead to a stronger response of the North African and Indian monsoon systems to the Holocene insolation forcing than of the East Asian monsoon and affect the seasonal distribution of Holocene rainfall variations. Within the Indian and North African monsoon domain, precipitation solely changes during the summer months, showing a decreasing Holocene precipitation trend. In the East Asian monsoon region, the precipitation signal is determined by an increasing precipitation trend during spring and a decreasing precipitation change during summer, partly balancing each other. A synthesis of reconstructions and the model results do not reveal an impact of the different seasonality on the timing of the Holocene rainfall optimum in the different sub-monsoon systems. They rather indicate locally inhomogeneous rainfall changes and show, that single palaeo-records should not be used to characterise the rainfall change and monsoon evolution for entire monsoon sub-systems.

scholarly journals Time-transgressive onset of the Holocene Optimum in the East Asian monsoon region

2016 ◽  
Vol 456 ◽  
pp. 39-46 ◽  
Author(s):  
Xin Zhou ◽  
Liguang Sun ◽  
Tao Zhan ◽  
Wen Huang ◽  
Xinying Zhou ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
The Holocene

scholarly journals Regionalization of Present-Day Precipitation in the Greater Monsoon Region of Asia*

2011 ◽  
Vol 24 (15) ◽  
pp. 4073-4095 ◽  
Author(s):  
Jessica L. Conroy ◽  
Jonathan T. Overpeck
Keyword(s):  
North Pacific ◽  
Arabian Sea ◽  
Western North Pacific ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Precipitation Variability ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
The Holocene

Abstract The spatial domain of the Asian monsoon has been defined by the intensity, seasonal concentration, and annual range of precipitation. Monsoon subdomains, such as the Indian monsoon, East Asian monsoon, and western North Pacific monsoon, have also been identified based on seasonal wind reversals as well as the timing and source of monsoon moisture. However, precipitation across the Asian monsoon region is heterogeneous and spatially complex and may have influences farther north than commonly assumed, particularly if scientists consider records of past variability spanning the current interglacial period. This paper presents an additional means of identifying the Asian monsoon domain and monsoon subsystems using an empirical orthogonal function (EOF)-based regionalization of gridded precipitation values. Regions of unique precipitation variability for the Asian monsoon region are determined using monthly precipitation anomalies from the Climate Prediction Center Merged Analysis of Precipitation (CMAP) gridded precipitation dataset from 1979 to 2009. From these regions, an area of Asian monsoon influence extending from the Arabian Sea eastward to the western North Pacific Ocean is defined, similar to other studies. One key difference is that this region of monsoon influence penetrates farther north into the Tibetan Plateau and northern China. Thus, paleoclimate observations of wetter conditions in these northern arid regions may suggest an intensification of monsoon moisture, rather than a northward shift in the boundary of the monsoon. In contrast, the Arabian Peninsula, largely removed from monsoon precipitation today, likely saw a shift of monsoon influence inland earlier in the Holocene. Also identified are different subdomains of distinct precipitation variability in southeastern Asia, the western North Pacific, and the East Asian monsoon region of northeastern China that agree with previous studies. Not identified in the paper is a single Indian summer monsoon region. Instead, the Arabian Sea was found to have unique precipitation variability relative to the Indian subcontinent. Summers with enhanced precipitation over the Arabian Sea coincide with decreased summer precipitation in the western North Pacific. This relationship is likely a result of the El Niño–Southern Oscillation (ENSO)-induced development of the Philippine Sea anticyclone. Local and remote sea surface temperatures were generally found to covary with regional precipitation, but not all regions respond similarly to the remote climate variability associated with ENSO. There is some evidence that the EOF-defined regions were stable … through the Holocene, although additional regionalization analyses of paleorecords and model simulations of past precipitation variability are needed to reconstruct past regions of coherent precipitation variability.

scholarly journals Characteristics of time-transgressive Holocene Optimum in the East Asian monsoon region

2019 ◽  
Vol 23 (3) ◽  
pp. 259-263 ◽  
Author(s):  
Ren Weihe ◽  
Guitian Yi
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Technological Development ◽  
East Asian ◽  
Temporal Patterns ◽  
The Tibetan Plateau ◽  
Monsoon Region ◽  
Spatial And Temporal Patterns ◽  
Asian Monsoon Region ◽  
The Holocene

The Holocene Optimum (HO) defines a relatively warm and wet period during the Holocene, the initial and termination ages of which have been extensively reported for East Asia; however, debates still focus on underlying spatial and temporal patterns. Here, latest paleoclimate records from the East Asian monsoon region and arid central Asia are synthesized to evaluate the spatial and temporal patterns of the HO. The results of this synthesis indicate that the latitude and both the initial and termination ages of the HO follow a strong relationship, which is an expansion and northward retreat of the HO except for records around the Tibetan Plateau and several other highlands. Both the HO and technological development are also suggested to have shaped the historic boom of the Neolithic human demography. This study provides a window toward an improved understanding of the characteristics of time-transgressive HO and allows to make predictions for the initial and termination ages of the HO at different geographical locations of the East Asian monsoon region.

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