Summer Rainfall Anomaly over Eastern China Teleconnected with Air-Sea Flux in East-Asia Seas

2017 ◽  
Vol 80 ◽  
pp. 18-23
Author(s):  
Qinghua Qi ◽  
Rongshuo Cai ◽  
Yashu Bai
Keyword(s):  
East Asia ◽  
Eastern China ◽  
Summer Rainfall ◽  
Rainfall Anomaly

Subseasonal Variation in ENSO-Related East Asian Rainfall Anomalies during Summer and Its Role in Weakening the Relationship between the ENSO and Summer Rainfall in Eastern China since the Late 1970s

2011 ◽  
Vol 24 (9) ◽  
pp. 2271-2284 ◽  
Author(s):  
Hong Ye ◽  
Riyu Lu
Keyword(s):  
Eastern China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Rainfall Anomaly ◽  
Precipitation Anomaly ◽  
Early Summer ◽  
Huai River ◽  
Rainfall Anomalies ◽  
Circulation Anomalies ◽  
The Relationship

Abstract The findings of the study reported in this paper show that, during ENSO decaying summers, rainfall and circulation anomalies exhibit clear subseasonal variation. Corresponding to a positive (negative) December–February (DJF) Niño-3.4 index, a positive (negative) subtropical rainfall anomaly, with a southwest–northeast tilt, appears in South China and the western North Pacific (WNP) in the subsequent early summer (from June to middle July) but advances northward into the Huai River Basin in China as well as Korea and central Japan in late summer (from late July to August). Concurrently, a lower-tropospheric anticyclonic anomaly over the WNP extends northward from early to late summer. The seasonal change in the basic flows, characterized by the northward shift of the upper-tropospheric westerly jet and the WNP subtropical high, is suggested to be responsible for the differences in the above rainfall and circulation anomalies between early and late summer by inducing distinct extratropical responses even under the almost identical tropical forcing of a precipitation anomaly in the Philippine Sea. A particular focus of the study is to investigate, using station rainfall data, the subseasonal variations in ENSO-related rainfall anomalies in eastern China since the 1950s, to attempt to examine their role in weakening the relationship between the ENSO and summer mean rainfall in eastern China since the late 1970s. It is found that the ENSO-related rainfall anomalies tend to be similar between early and late summer before the late 1970s, that is, the period characterized by a stronger ENSO–summer mean rainfall relationship. After the late 1970s, however, the anomalous rainfall pattern in eastern China is almost reversed between early and late summer, resulting accordingly in a weakened relationship between the ENSO and total summer rainfall in eastern China.

Regimes of Diurnal Variation of Summer Rainfall over Subtropical East Asia

2012 ◽  
Vol 25 (9) ◽  
pp. 3307-3320 ◽  
Author(s):  
Weihua Yuan ◽  
Rucong Yu ◽  
Minghua Zhang ◽  
Wuyin Lin ◽  
Haoming Chen ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
East Asia ◽  
Hydrological Cycle ◽  
Eastern China ◽  
Summer Rainfall ◽  
Early Morning ◽  
Rain Gauge ◽  
Western China ◽  
The Tibetan Plateau ◽  
Late Afternoon

Using hourly rain gauge records and Tropical Rainfall Measuring Mission 3B42 from 1998 to 2006, the authors present an analysis of the diurnal characteristics of summer rainfall over subtropical East Asia. The study shows that there are four different regimes of distinct diurnal variation of rainfall in both the rain gauge and the satellite data. They are located over the Tibetan Plateau with late-afternoon and midnight peaks, in the western China plain with midnight to early-morning peaks, in the eastern China plain with double peaks in late afternoon and early morning, and over the East China Sea with an early-morning peak. No propagation of diurnal phases is found from the land to the ocean across the coastlines. The different diurnal regimes are highly correlated with the inhomogeneous underlying surface, such as the plateau, plain, and ocean, with physical mechanisms consistent with the large-scale “mountain–valley” and “land–sea” breezes and convective instability. These diurnal characteristics over subtropical East Asia can be used as diagnostic metrics to evaluate the physical parameterization and hydrological cycle of climate models over East Asia.

scholarly journals Effect of Summer Arctic Sea Ice on the Reverse August Precipitation Anomaly in Eastern China between 1998 and 2016

2019 ◽  
Vol 32 (11) ◽  
pp. 3389-3407 ◽  
Author(s):  
Haibo Shen ◽  
Shengping He ◽  
Huijun Wang
Keyword(s):  
East Asia ◽  
Rossby Wave ◽  
Caspian Sea ◽  
Eastern China ◽  
Summer Rainfall ◽  
Precipitation Anomaly ◽  
The Caspian Sea ◽  
Southeastern China ◽  
Anomaly Pattern ◽  
Upper Level

Abstract The 1997/98 and 2015/16 El Niño episodes are regarded as two super–El Niño events and have exerted profound influence on eastern China summer rainfall, as expected. However, on the subseasonal time scale, summer rainfall in these two years shows dramatic diversity, although the characteristics of the two super–El Niños are similar. This study reveals that the rainfall increased (decreased) over central China (~30°–35°N) and decreased (increased) over southeastern China (south of ~25°N) in August 1998 (2016), exhibiting a dipole anomaly pattern over eastern China. Observational analyses indicate that, associated with negative interannual variability of the sea ice area (SIA) over the Barents–Kara Seas (BKS) in July and August, August rainfall shows significantly negative (positive) anomalies over central (southeastern) China. Further analyses reveal that negative SIA anomalies in the BKS induce significantly anomalous upper-level divergence over the polar region, accompanied with anomalous upper-level convergence over the Caspian Sea. The advection of vorticity by these anomalous divergent and convergent flows indicates notable Rossby wave sources near the Caspian Sea, yielding a Rossby wave train propagating eastward to East Asia that causes positive barotropic and baroclinic energy convection near the exit region of the Asian jet stream. The accumulation of perturbation energy in East Asia stimulates the formation of the Pacific–Japan teleconnection, which is favorable for the dipole rainfall anomaly pattern over eastern China. Thus, the positive and negative SIA anomaly over the BKS in 1998 and 2016 may contribute to the reverse August precipitation anomaly in eastern China.

Is the interdecadal variation of the summer rainfall over eastern China associated with SST?

2015 ◽  
Vol 46 (1-2) ◽  
pp. 135-146 ◽  
Author(s):  
Dong Si ◽  
Zeng-Zhen Hu ◽  
Arun Kumar ◽  
Bhaskar Jha ◽  
Peitao Peng ◽  
...  
Keyword(s):  
Eastern China ◽  
Summer Rainfall ◽  
Interdecadal Variation

The spring soil moisture and the summer rainfall in eastern China

2007 ◽  
Vol 52 (23) ◽  
pp. 3310-3312 ◽  
Author(s):  
ZhiYan Zuo ◽  
RenHe Zhang
Keyword(s):  
Soil Moisture ◽  
Eastern China ◽  
Summer Rainfall

Detection of Russian Fires Using MOPITT and MODIS Data

2005 ◽  
Vol 277-279 ◽  
pp. 816-823
Author(s):  
Sang Hee Lee ◽  
Gi Hyuk Choi ◽  
Hyo Suk Lim ◽  
Joo Hee Lee ◽  
Kwon Ho Lee ◽  
...  
Keyword(s):  
East Asia ◽  
Forest Fires ◽  
Eastern China ◽  
Northeast Asia ◽  
Smoke Aerosol ◽  
Modis Data ◽  
Smoke Pollution ◽  
Moderate Resolution ◽  
Large Fires ◽  
Moderate Resolution Imaging Spectroradiometer

The great fires were detected through the Moderate Resolution Imaging Spectroradiometer (MODIS) observations over Northeast Asia. The large amount of smoke produced near Lake Baikal was transported to East Asia using high Aerosol Optical Thickness (AOT) as seen through the satellite images. The smoke pollution from the Russian forest fires would sometimes reach Korea through Mongolia and eastern China. In May 2003, a number of large fires blazed through eastern Russian, producing a thick, widespread pall of smoke over much of East Asia. This study focuses on the identification of the carbon monoxide (CO) for MOPITT released from MOPITT primarily into East Asia during the Russian Fires. In the wake of the fires, the 700hPa MOPITT retrieved CO concentrations which reached up to 250ppbv. Smoke aerosol retrieval using a separation technique was also applied to the MODIS data observed in 14-22 May 2003. Large AOT, 2.0 ~ 5.0, was observed over Korea on 20 May 2003 due to the influence of the long range transport of smoke aerosol plume from the Russian Fires.

scholarly journals Impacts of Late-Spring North Eurasian Soil Moisture Variation on Summer Rainfall Anomalies in Northern East Asia

2021 ◽  
Author(s):  
Yinghan Sang ◽  
Hong-Li Ren ◽  
Yi Deng ◽  
Xiaofeng Xu ◽  
Xueli Shi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Temperature Gradient ◽  
East Asia ◽  
Summer Rainfall ◽  
Low Pressure ◽  
Late Spring ◽  
Boreal Summer ◽  
Pressure Center ◽  
North Eurasia ◽  
The Impact

Abstract This paper reports findings from a diagnostic and modeling analysis that investigates the impact of the late-spring soil moisture anomaly over North Eurasia on the boreal summer rainfall over northern East Asia (NEA). Soil moisture in May in the region from the Kara-Laptev Sea coasts to Central Siberian Plateau is found to be negatively correlated with the summer rainfall from Mongolia to Northeast China. The atmospheric circulation anomalies associated with the anomalously dry soil are characterized by a pressure dipole with the high-pressure center located over North Eurasia and the low-pressure center over NEA, where an anomalous lower-level moisture convergence occurs, favoring rainfall formation. Diagnoses and Modeling experiments demonstrate that the effect of the spring low soil moisture over North Eurasia may persist into the following summer through modulating local surface latent and sensible heat fluxes, increasing low-level air temperature at higher latitudes, and effectively reducing the meridional temperature gradient. The weakened temperature gradient could induce the decreased zonal wind and the generation of a low-pressure center over NEA, associated with a favorable condition of local synoptic activity. The above relationships and mechanisms are vice versa for the prior wetter soil and decreased NEA rainfall. These findings suggest that soil moisture anomalies over North Eurasia may act as a new precursor providing an additional predictability source for better predicting the summer rainfall in NEA.

scholarly journals Coupling Modes of Climatological Intraseasonal Oscillation in the East Asian Summer Monsoon

2016 ◽  
Vol 29 (17) ◽  
pp. 6363-6382 ◽  
Author(s):  
Zehao Song ◽  
Congwen Zhu ◽  
Jingzhi Su ◽  
Boqi Liu
Keyword(s):  
East Asia ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Diabatic Heating ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Intraseasonal Oscillation ◽  
Rainfall Anomaly ◽  
Asian Summer

Abstract The present study used harmonic and multivariate empirical orthogonal function (MV-EOF) analyses to identify the existence of climatological intraseasonal oscillation (CISO) in the diabatic heating, precipitation, and circulation of the East Asian summer monsoon (EASM). The strongest CISO signals are found in the north of the western North Pacific, possibly because of the horizontal gradient of diabatic heating induced by the seasonal land–sea thermal contrast. Further, the phase relationship between the diabatic heating components maintains the EASM CISO. The first two coupling modes of EASM CISO in the circulation are robust during May through August, with a period of 40–80 days, and exhibit phase locking to the stepwise establishment of the EASM, which reveals the coaction of the Mongolian cyclone (MC) around Lake Baikal at 850 hPa, the western North Pacific subtropical high (WNPSH) at 500 hPa, and the South Asian high (SAH) over the Tibetan Plateau (TP) at 200 hPa. The first mode shows that the jointly enhanced MC, WNPSH, and SAH correspond to a tripole rainfall anomaly with strong mei-yu and baiu fronts over East Asia. The second mode, however, indicates the eastward and northwestward propagation of MC and WNPSH, respectively, with suppressed SAH, as well as a dipole rainfall anomaly over East Asia. Both the observations and numerical simulation verify the importance of daily diabatic heating and SST in maintaining the CISO modes over the WNP, where the condensation heating related to atmospheric forcing determines the local intraseasonal air–sea interaction.

scholarly journals Variability and Mechanisms of Megadroughts over Eastern China during the Last Millennium: A Model Study

Atmosphere ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 7 ◽  
Author(s):  
Liang Ning ◽  
Jian Liu ◽  
Bin Wang ◽  
Kefan Chen ◽  
Mi Yan ◽  
...  
Keyword(s):  
East Asia ◽  
Eastern China ◽  
Western Pacific ◽  
Northwestern Pacific ◽  
Last Millennium ◽  
Internal Climate Variability ◽  
Model Study ◽  
External Forcings ◽  
Community Earth System Model ◽  
Sst Anomalies

The variability and mechanisms of multi-decadal megadroughts over eastern China during the last millennium were investigated using a control, full-forcing, and four sensitivity experiments from the Community Earth System Model (CESM) Last Millennium Ensemble (LME) archive. The model simulated megadroughts have comparable magnitudes and durations with those derived from reconstructed proxy data, although the megadroughts are not temporally synchronous. In all experiments, the megadroughts exhibit similar spatial structures, corresponding to a weakening of the East Asia summer monsoon (EASM) and a strengthening of the East Asia winter monsoon (EAWM). The results show that internal climate variability within the coupled climate system plays an essential role in triggering megadroughts, while different external forcings may contribute to persistence and modify the anomaly patterns of megadroughts. A pattern of meridional tripolar (warm-cold-warm) sea surface temperature (SST) anomalies in the western Pacific stretching from the equator to high latitude is responsible for the EASM weakening and EAWM strengthening. The weakening of the EASM and strengthening of the EAWM are essentially caused by negative SST anomalies over the northwestern Pacific and positive SST anomalies over the equatorial western Pacific, which are associated with a La Niña-like SST gradient across the tropical Pacific. The external forcings prolong the megadroughts through maintenance of the meridional tripolar SST anomalies and enlarge the megadrought spatial extent by magnifying the meridional tripolar SST anomalies.

scholarly journals MICS-Asia III: Multi-model comparison and evaluation of aerosol over East Asia

2019 ◽  
Author(s):  
Lei Chen ◽  
Yi Gao ◽  
Meigen Zhang ◽  
Joshua S. Fu ◽  
Jia Zhu ◽  
...  
Keyword(s):  
East Asia ◽  
Model Comparison ◽  
Process Analysis ◽  
Eastern China ◽  
Phase Iii ◽  
Chemical Components ◽  
Chemical Compositions ◽  
Air Pollution Control ◽  
Different Seasons ◽  
Simulation Results

Abstract. Fourteen chemical transport models (CTMs) participate in the MICS–Asia Phase III Topic 1. Their simulation results are compared with each other and with an extensive set of measurements, aiming to evaluate the current multi–scale air quality models’ ability in simulating aerosol species and to document similarities and differences among model performances, also to reveal the characteristics of aerosol chemical components over big cities in East Asia. In general, all participant models can reproduce the spatial distribution and seasonal variability of aerosol concentrations in the year 2010, and multi–model ensemble mean (EM) shows better performance than most individual models, with Rs ranging from 0.65 (NO3−) to 0.83 (PM2.5). Underestimations of BC (NMB = −17.0 %), SO42− (NMB = −19.1 %) and PM10 (NMB = −32.6 %) are simulated by EM, but positive biases are shown in NO3− (NMB = 4.9 %), NH4+ (NMB = 14.0 %) and PM2.5 (NMB = 4.4 %). Simulation results of BC, OC, SO42−, NO3− and NH4+ among CTMs are in good agreements, especially over polluted areas, such as the eastern China and the northern part of India. But large coefficients of variations (CV > 1.5) are also calculated over arid and semi–arid regions. This poor consistency among CTMs may attribute to their different processing capacities for dust aerosols. According to the simulation results in the six Asian cities from EM, different air–pollution control plans should be made due to their different major air pollutants in different seasons. Although a more considerable capacity for reproducing the concentrations of aerosol chemical compositions and their variation tendencies is shown in current CTMs by comparing statistics (e.g. RMSE and R) between MICS–Asia Phase II and Phase III, detailed process analysis and a fully understanding of the source–receptor relationship in each process may be helpful to explain and to reduce large diversities of simulated aerosol concentrations among CTMs, and these may be the potential development directions for future modeling studies in East Asia.

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