scholarly journals Relationship between interannual changes of summer rainfall over Yangtze River Valley and South China Sea–Philippine Sea: Possible impact of tropical zonal sea surface temperature gradient

2019 ◽  
Vol 39 (14) ◽  
pp. 5522-5538 ◽  
Author(s):  
Yao Ha ◽  
Zhong Zhong ◽  
Yun Zhang ◽  
Jinfeng Ding ◽  
Xiangrong Yang
Keyword(s):  
Temperature Gradient ◽  
South China Sea ◽  
Surface Temperature ◽  
South China ◽  
Yangtze River ◽  
Summer Rainfall ◽  
Yangtze River Valley ◽  
Sea Surface ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

scholarly journals Interdecadal Change in South China Sea Tropical Cyclone Frequency in Association with Zonal Sea Surface Temperature Gradient

2014 ◽  
Vol 27 (14) ◽  
pp. 5468-5480 ◽  
Author(s):  
Richard C. Y. Li ◽  
Wen Zhou
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Temperature Gradient ◽  
South China Sea ◽  
Surface Temperature ◽  
South China ◽  
Sea Surface ◽  
Period 2 ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

Abstract This study investigates the interdecadal changes in summertime tropical cyclone (TC) frequency over the South China Sea (SCS) during 1979–2010. Based on changepoint detection algorithms and spectral analysis, two inactive TC periods (period 1: 1979–93 and period 3: 2003–10) and one active TC period (period 2: 1994–2002) have been identified, with a dominant spectral peak of approximately 9–10 yr. Correlation analysis further reveals a significant negative relationship between TC frequency and the zonal sea surface temperature gradient (ZSG) between the northern Indian Ocean (NIO) and the western North Pacific (WNP) at both interannual and interdecadal time scales. That is, a positive ZSG between the NIO and the WNP tends to suppress cyclogenesis over the SCS, whereas a negative ZSG is generally favorable for SCS TC formation. The negative connection between cyclogenesis and ZSG may be explained by the influences of the ZSG on atmospheric circulations as well as Madden–Julian oscillation (MJO) activity over the SCS, which reveal prominent contrasts during the study periods. A positive ZSG between the tropical Pacific and the Indian Ocean induces an anomalous Walker-like circulation, which results in an anomalous subsidence and boundary layer divergence over the northern SCS. This also suppresses the moisture as well as MJO activity over the SCS, leading to a significant reduction in TC frequency during inactive periods 1 and 3. In contrast, a negative ZSG induces surface westerlies and favorable environmental conditions for TCs, thereby greatly enhancing SCS cyclogenesis during period 2.

What Controls the Mean East–West Sea Surface Temperature Gradient in the Equatorial Pacific: The Role of Cloud Albedo

2014 ◽  
Vol 27 (7) ◽  
pp. 2757-2778 ◽  
Author(s):  
N. J. Burls ◽  
A. V. Fedorov
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Walker Circulation ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Sea Surface Temperature Gradient ◽  
The Mean ◽  
East West ◽  
Surface Temperature Gradient

Abstract The mean east–west sea surface temperature gradient along the equator is a key feature of tropical climate. Tightly coupled to the atmospheric Walker circulation and the oceanic east–west thermocline tilt, it effectively defines tropical climate conditions. In the Pacific, its presence permits the El Niño–Southern Oscillation phenomenon. What determines this temperature gradient within the fully coupled ocean–atmosphere system is therefore a central question in climate dynamics, critical for understanding past and future climates. Using a comprehensive coupled model [Community Earth System Model (CESM)], the authors demonstrate how the meridional gradient in cloud albedo between the tropics and midlatitudes (Δα) sets the mean east–west sea surface temperature gradient in the equatorial Pacific. To change Δα in the numerical experiments, the authors change the optical properties of clouds by modifying the atmospheric water path, but only in the shortwave radiation scheme of the model. When Δα is varied from approximately −0.15 to 0.1, the east–west SST contrast in the equatorial Pacific reduces from 7.5°C to less than 1°C and the Walker circulation nearly collapses. These experiments reveal a near-linear dependence between Δα and the zonal temperature gradient, which generally agrees with results from the Coupled Model Intercomparison Project phase 5 (CMIP5) preindustrial control simulations. The authors explain the close relation between the two variables using an energy balance model incorporating the essential dynamics of the warm pool, cold tongue, and Walker circulation complex.

scholarly journals Forecast of summer precipitation in the Yangtze River Valley based on South China Sea springtime sea surface salinity

2019 ◽  
Vol 53 (9-10) ◽  
pp. 5495-5509 ◽  
Author(s):  
Lili Zeng ◽  
Raymond W. Schmitt ◽  
Laifang Li ◽  
Qiang Wang ◽  
Dongxiao Wang
Keyword(s):  
South China Sea ◽  
South China ◽  
Yangtze River ◽  
Summer Precipitation ◽  
Yangtze River Valley ◽  
River Valley ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
The Yangtze River ◽  
Surface Salinity

scholarly journals The role of the meridional sea surface temperature gradient in controlling the Caribbean low‐level jet

2017 ◽  
Vol 122 (11) ◽  
pp. 5903-5916 ◽  
Author(s):  
Tito Maldonado ◽  
Anna Rutgersson ◽  
Rodrigo Caballero ◽  
Francesco S. R. Pausata ◽  
Eric Alfaro ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Low Level ◽  
Sea Surface Temperature Gradient ◽  
Low Level Jet ◽  
The Caribbean ◽  
Surface Temperature Gradient

scholarly journals The West Pacific Gradient tracks ENSO and zonal Pacific sea surface temperature gradient during the last Millennium

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Zinke ◽  
S. A. Browning ◽  
A. Hoell ◽  
I. D. Goodwin
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Nino ◽  
Sea Surface ◽  
Last Millennium ◽  
The West ◽  
West Pacific ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

AbstractSmall changes in Pacific temperature gradients connected with the El Niño Southern Oscillation (ENSO) influence the Walker Circulation and are related to global climate anomalies. Therefore, it is of paramount importance to develop robust indices of their past behavior. Here, we reconstruct the difference in sea surface temperature between the west and central Pacific during ENSO, coined the West Pacific Gradient (WPG), based on the Last Millennium Paleo Hydrodynamics Data Assimilation. We show that the WPG tracks ENSO variability and strongly co-varies with the zonal gradient in Pacific sea surface temperature. We demonstrate that the WPG strength is related to significant atmospheric circulation and precipitation anomalies during historical El Niño and La Niña events by magnifying or weakening droughts and pluvials across the Indo-Pacific. We show that an extreme negative WPG coupled to a strong zonal Pacific temperature gradient is associated with enhanced megadroughts in North America between 1400 CE and the late sixteenth century. The twentieth century stands out in showing the most extreme swings between positive and negative WPG conditions over the past Millennium. We conclude that the WPG is a robust index together with ENSO indices to reveal past changes in Pacific zonal sea surface temperature gradient variability.

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