scholarly journals Disentangling Impacts of Dynamic and Thermodynamic Components on Late Summer Rainfall Anomalies in East Asia

2018 ◽  
Vol 123 (16) ◽  
pp. 8623-8633 ◽  
Author(s):  
Hyoeun Oh ◽  
Kyung-Ja Ha ◽  
Axel Timmermann
Keyword(s):  
East Asia ◽  
Late Summer ◽  
Summer Rainfall ◽  
Rainfall Anomalies

Distinct Principal Modes of Early and Late Summer Rainfall Anomalies in East Asia*

2009 ◽  
Vol 22 (13) ◽  
pp. 3864-3875 ◽  
Author(s):  
Bin Wang ◽  
Jian Liu ◽  
Jing Yang ◽  
Tianjun Zhou ◽  
Zhiwei Wu
Keyword(s):  
East Asia ◽  
Summer Monsoon ◽  
Land Surface ◽  
Southern Oscillation ◽  
Southern China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Seasonal Prediction ◽  
Early Summer ◽  
Rainfall Anomalies

Abstract The current seasonal prediction of East Asia (EA) summer monsoon deals with June–July–August (JJA) mean anomalies. This study shows that the EA summer monsoon may be divided into early summer [May–June (MJ)] and late summer [July–August (JA)] and exhibits remarkable differences in mean state between MJ and JA. This study reveals that the principal modes of interannual precipitation variability have distinct spatial and temporal structures during the early and late summer. These principal modes can be categorized as either El Niño–Southern Oscillation (ENSO) related or non-ENSO related. During the period of 1979–2007, ENSO-related modes explain 35% of MJ variance and 45% of JA variance, and non-ENSO-related modes account for 25% of MJ variance and 20% of JA variance. For ENSO-related variance, about two-thirds are associated with ENSO decaying phases, and one-third is associated with ENSO developing phases. The ENSO-related MJ modes generally concur with rapid decay or early development of ENSO episodes, and the opposite tends to apply to ENSO-related JA modes. The non-ENSO MJ mode is preceded by anomalous land surface temperatures over southern China during the previous March and April. The non-ENSO JA mode is preceded by lasting equatorial western Pacific (the Niño-4 region) warming from the previous winter through late summer. The results suggest that 1) prediction of bimonthly (MJ) and (JA) anomalies may be useful, 2) accurate prediction of the detailed evolution of ENSO is critical for prediction of ENSO-related bimonthly rainfall anomalies over East Asia, and 3) non-ENSO-related modes are of paramount importance during ENSO neutral years. Further establishment of the physical linkages between the non-ENSO modes and their corresponding precursors may provide additional sources for EA summer monsoon prediction.

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.

scholarly journals Weakened Connection between East China Summer Rainfall and the East Asia-Pacific Teleconnection Pattern

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 704
Author(s):  
Xiaoxue Yin ◽  
Lian-Tong Zhou ◽  
Jingliang Huangfu
Keyword(s):  
East Asia ◽  
Vertical Motion ◽  
Summer Rainfall ◽  
Teleconnection Pattern ◽  
Asia Pacific ◽  
East China ◽  
Boreal Summer ◽  
Interdecadal Change ◽  
Rainfall Anomalies ◽  
Action Center

The interdecadal change in the relationship between the East Asia-Pacific (EAP) teleconnection pattern and rainfall over East China during boreal summer (June–August) was investigated using observation and reanalysis datasets during 1951–2018. As proposed in a previous study, summer rainfall in the Yangtze-Huaihe River (YH-R) valley is below (above) normal when a positive (negative) EAP event occurs. Based on the close relationship with the rainfall anomalies, the EAP teleconnection pattern has been widely used in the prediction of summer rainfall variations in the YH-R valley. However, we found that the rainfall anomalies in the YH-R basin associated with the EAP pattern were weaker and less evident after the late 1980s. This finding indicates a decreased relationship between the EAP pattern and YH-R basin summer rainfall after the late 1980s, and a decrease in the quality and skill of seasonal predictions of YH-R basin summer rainfall related to the EAP pattern. This pronounced weakening in the YH-R summer rainfall-EAP pattern connection is attributed to the northeastward displacement of the Japanese action center of the EAP pattern after the late 1980s, which caused weaker anomalous vertical motion and moisture transportation over the YH-R valley. The present research reveals that the interdecadal expansion in the size of the Indo-Pacific warm pool in the late 1980s is likely responsible for the northeastward shift in the Japanese action center of the EAP teleconnection pattern by modulating anomalous convective activities and the northward propagation of the EAP pattern.

scholarly journals Lengthening of summer season over the Northern Hemisphere under 1.5°C and 2.0°C global warming

2021 ◽  
Author(s):  
Bo-Joung Park ◽  
Seung-Ki Min ◽  
Evan Weller
Keyword(s):  
Global Warming ◽  
East Asia ◽  
Northern Hemisphere ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Late Summer ◽  
Industrial Condition ◽  
Summer Season ◽  
Hot Days

Abstract Summer season has lengthened substantially across Northern Hemisphere (NH) land over the past decades, which has been attributed to anthropogenic greenhouse gas increases. This study examines additional future changes in summer season onset and withdrawal under 1.5℃ and 2.0℃ global warming conditions using multiple atmospheric global climate model (AGCM) large-ensemble simulations from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project. Five AGCMs provide more than 100 runs of 10-year length for three experiments: All-Hist (current decade: 2006-2015), Plus15, and Plus20 (1.5℃ and 2.0℃ above pre-industrial condition, respectively). Results show that with 1.5℃ and 2.0℃ warmer conditions summer season will become longer by a few days to weeks over entire NH lands, with slightly larger contributions by delay in withdrawal due to stronger warming in late summer. Stronger changes are observed more in middle latitudes than high latitudes and largest expansion (up to three weeks) is found over East Asia and the Mediterranean. Associated changes in summer-like day frequency is further analyzed focusing on the extended summer edges. The hot days occur more frequently in lower latitudes including East Asia, USA and Mediterranean, in accord with largest summer season lengthening. Further, difference between Plus15 and Plus20 indicates that summer season lengthening and associated increases in hot days can be reduced significantly if warming is limited to 1.5℃. Overall, similar results are obtained from CMIP5 coupled GCM simulations (based on RCP8.5 scenario experiments), suggesting a weak influence of air-sea coupling on summer season timing changes.

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 Oceanic Forcings of the Interdecadal Variability in East Asian Summer Rainfall

2016 ◽  
Vol 29 (21) ◽  
pp. 7633-7649 ◽  
Author(s):  
Dong Si ◽  
Yihui Ding
Keyword(s):  
Yangtze River ◽  
Summer Rainfall ◽  
Yangtze River Valley ◽  
River Valley ◽  
Interdecadal Variability ◽  
Huaihe River ◽  
Huaihe River Valley ◽  
Leading Mode ◽  
Rainfall Anomalies ◽  
The 1960S

Abstract In this study, it was found that the Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation (AMO) are shown to be the two major drivers of the interdecadal variability of summer rainfall over East Asia. The first leading mode (PC1) of this interdecadal variability—associated with an in-phase variation of rainfall anomalies along the Yangtze River valley and Huanghe–Huaihe River valley in China—is attributed to the PDO, while the second leading mode (PC2)—associated with seesawlike rainfall anomalies between the Yangtze River valley and Huanghe–Huaihe River valley—is attributed to the AMO. The AMO teleconnects its influence to the East Asian region, and beyond, through a circumglobal stationary baroclinic wave train extending from the Atlantic Ocean, through the Eurasian continent, and extending to North America. The AMO also altered the nature of the PDO through this atmospheric teleconnection, resulting in the occurrence of a different PDO pattern (“pseudo-PDO”) between the 1960s and 2010s. The pseudo-PDO has a different anomalous SST pattern in both the tropical and midlatitude Pacific compared to the conventional PDO. The pseudo-PDO causes a distinct atmospheric response in East Asia leading to an opposite relationship with the PC1 compared to the conventional PDO, thus leading to a change in the direction of the influence of the PDO on PC1 between the 1880s–1950s and the 1960s–2010s.

Phenology and field biology of the dung beetle onitis caffer Boheman (Coleoptera: Scarabaeidae) in southern Africa

1986 ◽  
Vol 76 (3) ◽  
pp. 433-446 ◽  
Author(s):  
Penelope B. Edwards
Keyword(s):  
Late Summer ◽  
Summer Rainfall ◽  
Dung Beetle ◽  
Immature Stages ◽  
Average Depth ◽  
Winter Rainfall ◽  
The Third ◽  
Field Biology ◽  
June July ◽  
Third Instar Larvae

AbstractThe biology and development of immature stages of summer (SR) and winter rainfall (WR) strains of Onitis caffer Boheman were studied in South Africa in a summer rainfall area (Pretoria). A pair of adult beetles buried up to 650 ml of dung from one dung pad, and females laid an average of 1 egg for every 62 ml of dung buried. Broods were buried at an average depth of 50 cm in watered soil and 24 cm in unwatered soil. Eggs laid in June (winter) hatched 10 weeks later. The third instar was reached by late October. WR larvae suffered higher mortality (82%) with the onset of summer rains than did SR larvae (53%). By the following June, 6% of surviving WR individuals had emerged as adults, 12% were adults in faecal shells and 82% were diapausing third-instar larvae. Of the SR individuals, 67% emerged by June and 33% were diapausing third-instar larvae. In a second experiment, two groups of broods of the SR strain of O. caffer of different ages were set out in the field in June. One group, equivalent to broods produced early in the season (March), entered diapause as third-instar larvae, and adults emerged the following autumn. The second group represented broods produced later in the season (May); the majority did not diapause, but adults also emerged the following autumn. A field population of SR adults of O. caffer was sampled for two years. Adults were first recorded at the end of February (late summer), and newly-emerged specimens were caught up until the end of April. Maximum numbers were recorded in late March to early April (autumn), and activity ceased in June-July (winter).

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