Enhanced influence of early-spring tropical Indian Ocean SST on the following early-summer precipitation over Northeast China

2017 ◽  
Vol 51 (11-12) ◽  
pp. 4065-4076 ◽  
Author(s):  
Tingting Han ◽  
Shengping He ◽  
Huijun Wang ◽  
Xin Hao
Keyword(s):  
Indian Ocean ◽  
Northeast China ◽  
Summer Precipitation ◽  
Tropical Indian Ocean ◽  
Early Spring ◽  
Early Summer

scholarly journals Variability of Summer Rainfall in Northeast China and Its Connection with Spring Rainfall Variability in the Huang-Huai Region and Indian Ocean SST

2014 ◽  
Vol 27 (18) ◽  
pp. 7086-7101 ◽  
Author(s):  
Zongting Gao ◽  
Zeng-Zhen Hu ◽  
Jieshun Zhu ◽  
Song Yang ◽  
Rong-Hua Zhang ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Northeast China ◽  
General Circulation ◽  
Tropical Indian Ocean ◽  
Summer Rainfall ◽  
Rainfall Anomaly ◽  
Atmospheric Modeling ◽  
Late Spring ◽  
Local Soil ◽  
The Impact

Abstract In this work, the variability of summer [June–August (JJA)] rainfall in northeast China is examined and its predictors are identified based on observational analyses and atmospheric modeling experiments. At interannual time scales, the summer rainfall anomaly in northeast China is significantly correlated with the rainfall anomaly over the Huang-Huai region (32°–38°N, 105°–120°E) in late spring (April–May). Compared with climatology, an earlier (later) rainy season in the Huang-Huai region favors a wet (dry) summer in northeast China. Also, this connection has strengthened since the late 1970s. In addition to the impact of the sea surface temperature anomaly (SSTA) in the tropical Indian Ocean, the local soil moisture anomalies caused by the rainfall anomaly in the Huang-Huai region in late spring generate summer general circulation anomalies, which contribute to the rainfall anomaly in northeast China. As a result, when compared with the SSTA, the rainfall anomaly in the Huang-Huai region in late spring can be used as another and even better predictor for the summer rainfall anomaly in northeast China. The results from atmospheric general circulation model experiments forced by observed SST confirm the diagnostic results to some extent, including the connection of the rainfall anomaly between the Huang-Huai region in April–May and northeastern China in JJA as well as the influence from SSTA in the tropical Indian Ocean. It is shown that eliminating the internal dynamical processes by using the ensemble mean intensifies the connection, implying that the connection of rainfall variation in the two different seasons/regions may be partially caused by the external forcing (e.g., SSTA in the tropical Indian Ocean).

scholarly journals The Indian Ocean SST Link to Solar Induced Chlorophyll Fluorescence Over India During Early Summer Monsoon

2021 ◽  
Author(s):  
Roma Varghese ◽  
Swadhin K. Behera ◽  
Mukunda Dev Behera
Keyword(s):  
Chlorophyll Fluorescence ◽  
Indian Ocean ◽  
Summer Monsoon ◽  
Tropical Indian Ocean ◽  
Early Summer ◽  
Terrestrial Vegetation ◽  
Atmospheric Teleconnections ◽  
Monsoon Flow ◽  
The Indian Ocean ◽  
Sst Anomalies

Abstract This is a maiden attempt to explore the influence of sea surface temperature (SST) variations in the tropical Indian Ocean on the gross primary productivity (GPP) of the terrestrial vegetation of India during the summer monsoon. We studied the productivity of the vegetation across India using solar-induced chlorophyll fluorescence (SIF) as a proxy. Our results demonstrated a strong negative SST–SIF relationship: the productivity decreases (increases) when the SST of the tropical Indian Ocean is higher (lower) than normal. This SST–SIF coupling observed during June can be explained through the atmospheric teleconnections. Positive SST anomalies weaken the land–ocean thermal gradient during the monsoon onset period, reduce the monsoon flow, and hence decrease the moisture transport from the ocean to the Indian mainland. The resultant water stress, along with the high air temperature, leads to a reduction in the GPP. Conversely, negative SST anomalies strengthen the monsoon and increase the availability of moisture for photosynthesis. There is scope for improving regional GPP forecasting studies using the observed SST–SIF relationships.

scholarly journals Extreme IOD induced tropical Indian Ocean warming in 2020

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ying Zhang ◽  
Yan Du
Keyword(s):  
Indian Ocean ◽  
Surface Wind ◽  
Tropical Indian Ocean ◽  
First Record ◽  
Early Summer ◽  
Wind Anomaly ◽  
Surface Warming ◽  
Positive Indian Ocean Dipole ◽  
Indian Ocean Warming ◽  
The 1960S

AbstractThe tropical Indian Ocean (TIO) basin-wide warming occurred in 2020, following an extreme positive Indian Ocean Dipole (IOD) event instead of an El Niño event, which is the first record since the 1960s. The extreme 2019 IOD induced the oceanic downwelling Rossby waves and thermocline warming in the southwest TIO, leading to sea surface warming via thermocline-SST feedback during late 2019 to early 2020. The southwest TIO warming triggered equatorially antisymmetric SST, precipitation, and surface wind patterns from spring to early summer. Subsequently, the cross-equatorial “C-shaped” wind anomaly, with northeasterly–northwesterly wind anomaly north–south of the equator, led to basin-wide warming through wind-evaporation-SST feedback in summer. This study reveals the important role of air–sea coupling processes associated with the independent and extreme IOD in the TIO basin-warming mode, which allows us to rethink the dynamic connections between the Indo-Pacific climate modes.

scholarly journals The Impact of Tropical Indian Ocean Variability on Summer Surface Air Temperature in China

2011 ◽  
Vol 24 (20) ◽  
pp. 5365-5377 ◽  
Author(s):  
Kaiming Hu ◽  
Gang Huang ◽  
Ronghui Huang
Keyword(s):  
Indian Ocean ◽  
Air Temperature ◽  
South China ◽  
Northeast China ◽  
Surface Air Temperature ◽  
Vertical Motion ◽  
Tropical Indian Ocean ◽  
Ocean Basin ◽  
Sst Anomalies ◽  
Anomalous Cyclone

Abstract Evidence is presented that the boreal summer surface air temperature over south China and northeast China is remotely influenced by the Indian Ocean Basin mode (IOBM) sea surface temperature (SST) anomalies. Above-normal temperature in south China and below-normal temperature in northeast China correspond to a simultaneous Indian Ocean Basin warming. The teleconnection from Indian Ocean SST anomalies to China summer surface air temperature is investigated using observations and an atmospheric general circulation model (AGCM). The results herein indicate that the tropical Indian Ocean Basin warming can trigger a low-level anomalous anticyclone circulation in the subtropical northwest Pacific and an anomalous cyclone circulation in midlatitude East Asia through emanating a baroclinic Kelvin wave. In south China, the reduced rainfall and downward vertical motion associated with the anomalous low-level anticyclone circulation lead to above-normal summer surface air temperature. In northeast China, by contrast, upward vertical motion associated with the anomalous cyclone leads to below-normal summer surface air temperature.

Strengthening of Tropical Indian Ocean Teleconnection to the Northwest Pacific since the Mid-1970s: An Atmospheric GCM Study*

2010 ◽  
Vol 23 (19) ◽  
pp. 5294-5304 ◽  
Author(s):  
Gang Huang ◽  
Kaiming Hu ◽  
Shang-Ping Xie
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Tropical Indian Ocean ◽  
Early Summer ◽  
Interdecadal Change ◽  
Northwest Pacific ◽  
Wind Pattern ◽  
Climate Anomalies

Abstract The correlation of northwest (NW) Pacific climate anomalies during summer with El Niño–Southern Oscillation (ENSO) in the preceding winter strengthens in the mid-1970s and remains high. This study investigates the hypothesis that the tropical Indian Ocean (TIO) response to ENSO is key to this interdecadal change, using a 21-member ensemble simulation with the Community Atmosphere Model, version 3 (CAM3) forced by the observed history of sea surface temperature (SST) for 1950–2000. In the model hindcast, the TIO influence on the summer NW Pacific strengthens in the mid-1970s, and the strengthened TIO teleconnection coincides with an intensification of summer SST variability over the TIO. This result is corroborated by the fact the model’s skills in simulating NW Pacific climate anomalies during summer increase after the 1970s shift. During late spring to early summer, El Niño–induced TIO warming decays rapidly for the epoch prior to the 1970s shift but grows and persists through summer for the epoch occurring after it. This difference in the evolution of the TIO warming determines the strength of the TIO teleconnection to the NW Pacific in the subsequent summer. An antisymmetric wind pattern develops in spring across the equator over the TIO, and the associated northeasterly anomalies aid the summer warming over the north Indian Ocean by opposing the prevailing southwest monsoon. In the model, this antisymmetric spring wind pattern is well developed after but absent before the 1970s shift.

scholarly journals Possible Causes of Extremely Warm Early Summer in North China During Cold and Warm Periods

2021 ◽  
Vol 3 ◽  
Author(s):  
Xiaofan Li ◽  
Zhiping Yao ◽  
Xiaojuan Wang ◽  
Changwen Yu ◽  
Shaojing Che ◽  
...  
Keyword(s):  
Indian Ocean ◽  
North China ◽  
Tropical Indian Ocean ◽  
Western Pacific Subtropical High ◽  
Early Summer ◽  
Circulation System ◽  
Positive Temperature ◽  
Temperature Anomalies ◽  
Major Factors ◽  
The Kuroshio

The abnormal characteristics of extremely warm early summer (EWES) in North China under different decadal backgrounds were contrastively analyzed. Their relationships with upper- and lower-level atmospheric circulation and global sea surface temperature anomalies (SSTAs) are also discussed. Results show that temperature anomalies of EWES in North China are overall higher than normal in both cold (1961–1993) and warm (1994–2019) periods, but the anomalies of the latter are much higher than that of the former. EWES in North China is directly related to the circulation lying between 40° and 50°N in the middle troposphere, which leads to positive temperature anomalies occurring from the bottom to the upper level of the troposphere together with a high anomaly trend tilting northward. The persistent and strong Eurasian continental high (ECH) and weak Northeast China cold vortex (NECV) activity, together with the strong western Pacific subtropical high (WPSH) are major factors that directly lead to EWES in North China. ECH and WPSH are stronger and larger, and NECV are weaker and more northward in the warm period than in the cold period. In addition, the positive SSTAs in the tropical Indian Ocean and the Kuroshio area are favorable for the stronger and larger ECH and WPSH as well as the weaker and more northward NECV, causing strong anticyclonic and downward circulation system controlling North China, resulting in the extremely warm temperatures there. The joint impact of the positive tropical Indian Ocean SSTAs and the Kuroshio region SSTAs is more significant during warm than cold periods, resulting in much stronger EWES in North China during warm periods.

scholarly journals The Northward-Propagating Intraseasonal Oscillations in the Northern Indian Ocean during Spring–Early Summer

2018 ◽  
Vol 31 (17) ◽  
pp. 7003-7017 ◽  
Author(s):  
Kuiping Li ◽  
Lin Feng ◽  
Yanliang Liu ◽  
Yang Yang ◽  
Zhi Li ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Vertical Wind Shear ◽  
Tropical Indian Ocean ◽  
Active Regions ◽  
Atmospheric Model ◽  
Early Summer ◽  
Surface Moisture ◽  
Intraseasonal Oscillations ◽  
Northern Bay Of Bengal ◽  
Two Stages

The intraseasonal oscillations (ISOs) activate in the tropical Indian Ocean (IO), exhibiting distinct seasonal contrasts in active regions and propagating features. The seasonal northward migration of the ISO activity initiates in spring–early summer, composed of two stages. Strong ISO activity first penetrates into the northern Bay of Bengal (BoB) around mid-April, and then extends to the northern Arabian Sea (AS) by mid-May. The northward-propagating ISOs (NPISOs) during their initiation periods, which are referred to as the primary northward-propagating (PNP) events, are analyzed with regard to the BoB and the AS, respectively. In terms of the BoB PNP event, the northward branch could be observed only in the BoB, and the eastward movement is still clear as the winter ISOs. For the AS PNP event, a strong northward branch spreads across the wider northern IO, as obvious as the summer ISOs. The relative roles of the seasonal environmental fields in modulating the PNP events are diagnosed based on a 2.5-layer atmospheric model. The results indicate that the seasonal variations of the surface moisture dominantly regulate the BoB PNP event, while both the surface moisture and the vertical wind shear are necessary for the AS PNP event. Additionally, the leading BoB PNP event is hypothesized to potentially act as a precondition of the following AS PNP event in terms of their internal ISO reinitiation processes and in terms of creating a favorable easterly shear environment in the northern IO.

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