scholarly journals The Capability of ENSEMBLES Models in Predicting the Principal Modes of Pan-Asian Monsoon Precipitation

2015 ◽  
Vol 28 (21) ◽  
pp. 8486-8510 ◽  
Author(s):  
Ya Gao ◽  
Huijun Wang ◽  
Dong Chen
Keyword(s):  
Asian Monsoon ◽  
Southern Oscillation ◽  
Summer Precipitation ◽  
Tropical Indian Ocean ◽  
Spatiotemporal Distribution ◽  
Monsoon Region ◽  
Coupled Models ◽  
Asian Monsoon Region ◽  
Second Mode ◽  
Ensembles Project

Abstract The predictability of the dominant modes of summer (June–September) precipitation in the pan-Asian monsoon region is evaluated based on 1-month-lead retrospective forecasts in five state-of-the-art coupled models from the ENSEMBLES project for the period 1979–2005. The results show that the models and their multimodel ensemble mean (MME) perform well in reproducing the interannual variability of the climatology and the spatiotemporal distribution of the first mode of summer precipitation in the pan-Asian monsoon region. The associated oceanic and atmospheric circulation indicators are also well captured, such as the spatiotemporal structures of the simultaneous El Niño–Southern Oscillation (ENSO) and Antarctic Oscillation in the Pacific Ocean (AAOSP). Moreover, the interannual variation of the preceding AAOSP can also be captured by some of the coupled models. For individual models, the ECMWF, Météo-France, and Met Office models exhibit better skill with respect to the first mode of summer precipitation in the pan-Asian monsoon region, which displays a tripole pattern from north to south over 80°–140°E. In addition, these models can successfully predict the intensity and location of the associated ENSO, as well as the simultaneous summer AAOSP distributions. By contrast, the prediction capabilities of the Leibniz Institute of Marine Sciences (IFM-GEOMAR) and Euro-Mediterranean Center for Climate Change (CMCC-INGV) models are relatively weaker. Furthermore, the predictions of the second mode of the summer precipitation in the pan-Asian monsoon region are investigated. Some of the ENSEMBLES models show good capability in predicting the spatiotemporal distribution of the second mode, owing to the successful prediction of the atmospheric convection activities over the tropical Indian Ocean.

scholarly journals Effects of changes in moisture source and the upstream rainout on stable isotopes in summer precipitation – a case study in Nanjing, East China

2015 ◽  
Vol 12 (4) ◽  
pp. 3919-3944 ◽  
Author(s):  
Y. Tang ◽  
H. Pang ◽  
W. Zhang ◽  
Y. Li ◽  
S. Wu ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Isotopic Composition ◽  
Asian Monsoon ◽  
Summer Precipitation ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Moisture Source ◽  
Source Regions ◽  
Stable Isotopic Composition ◽  
Stable Isotopic

Abstract. In the Asian monsoon region, variations in the stable isotopic composition of speleothems have often been attributed to the "amount effect". However, an increasing number of studies suggest that the "amount effect" in local precipitation is insignificant or even non-existent. To explore this issue further, we examined the variability of daily stable isotopic composition (δ18O) in summer precipitation of 2012–2014 in Nanjing, East China. We found that δ18O was not significantly correlated with local rainfall amount, but could be linked to changes in the location and rainout processes of precipitation source regions. Our findings suggest that the stable isotopes in precipitation could signal the location shift of precipitation source regions in the intertropical convergence zone (ITCZ) over the course of the monsoon season. As a result, changes in moisture source location and upstream rainout effect should be taken into account when interpreting the stable isotopic composition of speleothems in the Asian monsoon region.

Climate response to anthropogenic aerosols and related SST variabilities including ENSO in the Asian monsoon region

2021 ◽  
Author(s):  
Sho Kitabayashi ◽  
Hiroshi G. Takahashi
Keyword(s):  
Air Temperature ◽  
Asian Monsoon ◽  
Southern Oscillation ◽  
Surface Air Temperature ◽  
Primary Component ◽  
Climate Response ◽  
Monsoon Region ◽  
Anthropogenic Aerosols ◽  
Asian Monsoon Region ◽  
The Impact

<div> <div>Over the past decades, the emission of anthropogenic aerosols in the Asian monsoon region is increasing. This change alters the climate condition, such as the Asian monsoon precipitation, through the aerosol–radiation and –cloud interactions (ACI). Previous studies pointed out that the slow response to aerosols, through the SST change induced by ACI, particularly around the Maritime Continent (MC), was the primary component of climate response to aerosols. Dynamical ocean feedbacks through ACI modify the Asian monsoon circulations and precipitation. Over and around the MC, the amount of aerosol was likely to be affected by the El Niño–Southern Oscillation (ENSO). </div> <div>The aim of the study is to evaluate the climate response to anthropogenic aerosols in the Asian monsoon region. Also, we understand the relationship with SST change, including ENSO. To isolate the impact of anthropogenic aerosols, we analyzed the historical climate experiment (HIST) and the climate experiment with fixed aerosols at the preindustrial era (hist-piAer), which were provided in the CMIP6. As a result, the climatological mean surface air temperature in HIST was lower over most parts of the world than that in hist-piAer. However, a warm surface air temperature signal was found in the northern part of India, particularly in JJA during the rainy season. Also, there were dry signals in India and other Eurasia regions. We will also analyze fixed-SST historical simulation to identify physical process, including SST-related process.</div> </div>

scholarly journals What controls the stable isotope composition of precipitation in the Asian monsoon region?

2017 ◽  
Author(s):  
Le Duy Nguyen ◽  
Ingo Heidbüchel ◽  
Hanno Meyer ◽  
Bruno Merz ◽  
Heiko Apel
Keyword(s):  
Isotopic Composition ◽  
Asian Monsoon ◽  
Precipitation Amount ◽  
Climatic Conditions ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Air Mass ◽  
Local Factors ◽  
Regional Factors ◽  
Isotopic Records

Abstract. This study analyzes the influence of local and regional climatic factors on the stable isotopic composition of rainfall in the Vietnamese Mekong Delta as part of the Asian monsoon region. It is based on 1.5 years of weekly rainfall samples. Their isotopic content is analyzed by Local Meteoric Water Lines (LMWL) and single-factor regressions. Additionally, the contribution of several regional and local factors is quantified by multiple linear regressions (MLR) of all possible factor combinations and by relative importance analysis, a novel approach for the interpretation of isotopic records. The local factors are extracted from local climate records, while the regional factors are derived from atmospheric backward trajectories of water particles. The regional factors, i.e. precipitation, temperature, relative humidity and moving distance of the backward trajectories, are combined with equivalent local climatic parameters to predict the response variables δ18O, δ2H, and d-excess of precipitation at the station of measurement. The results indicate that (i) MLR can much better explain the isotopic variation of precipitation (R2 = 0.8) compared to single-factor linear regression (R2 = 0.3); (ii) the isotopic variation in precipitation is controlled dominantly by regional moisture regimes (~ 70 %) compared to local climatic conditions (~ 30 %); (iii) the most important climatic parameter during the early rainy season is the precipitation amount along the trajectories of air mass movements; (iv) the influence of local precipitation amount and temperature is not significant during the early rainy season, unlike the regional precipitation amount effect; (v) secondary fractionation processes (e.g. sub-cloud evaporation) take place mainly in the dry season, either locally for δ18O and δ2H, or along the air mass trajectories for d-excess. The analysis shows that regional and local factors vary in importance over the seasons, and that the source regions and transport pathways, and in particular the climatic conditions along the pathways, have a large influence on the isotopic composition of rainfall. The proposed methods thus proved to be valuable for the interpretation of the isotopic records in rainfall and the factors controlling it. The results illustrate that the interpretation of the isotopic composition in precipitation as a recorder of local climatic conditions, as for example performed for paleo records of water isotopes, may not be adequate in the Southern part of the Indochinese Peninsula, and likely also not in other regions affected by monsoon processes. However, the presented approach could open a pathway towards better and seasonally differentiated reconstruction of paleoclimates based on isotopic records.

Temperature signals of ice core and speleothem isotopic records from Asian monsoon region as indicated by precipitation δ18O

2021 ◽  
Vol 554 ◽  
pp. 116665
Author(s):  
Wusheng Yu ◽  
Tandong Yao ◽  
Lonnie G. Thompson ◽  
Jean Jouzel ◽  
Huabiao Zhao ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Ice Core ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Isotopic Records ◽  
Precipitation Δ18o
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