Estimation of net surface shortwave radiation over the tropical Indian Ocean using geostationary satellite observations: Algorithm and validation

2011 ◽  
Vol 116 (C9) ◽  
Author(s):  
Naveen R. Shahi ◽  
Pradeep K. Thapliyal ◽  
Rashmi Sharma ◽  
Pradip K. Pal ◽  
Abhijit Sarkar
2010 ◽  
Vol 7 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Naveen R. Shahi ◽  
Neeraj Agarwal ◽  
Rashmi Sharma ◽  
Pradeep K. Thapliyal ◽  
Prakash. C. Joshi ◽  
...  

2010 ◽  
Vol 23 (4) ◽  
pp. 947-965 ◽  
Author(s):  
Gregory R. Foltz ◽  
Jérôme Vialard ◽  
B. Praveen Kumar ◽  
Michael J. McPhaden

Abstract Sea surface temperature (SST) in the southwestern tropical Indian Ocean exerts a significant influence on global climate through its influence on the Indian summer monsoon and Northern Hemisphere atmospheric circulation. In this study, measurements from a long-term moored buoy are used in conjunction with satellite, in situ, and atmospheric reanalysis datasets to analyze the seasonal mixed layer heat balance in the thermocline ridge region of the southwestern tropical Indian Ocean. This region is characterized by a shallow mean thermocline (90 m, as measured by the 20°C isotherm) and pronounced seasonal cycles of Ekman pumping and SST (seasonal ranges of −0.1 to 0.6 m day−1 and 26°–29.5°C, respectively). It is found that surface heat fluxes and horizontal heat advection contribute significantly to the seasonal cycle of mixed layer heat storage. The net surface heat flux tends to warm the mixed layer throughout the year and is strongest during boreal fall and winter, when surface shortwave radiation is highest and latent heat loss is weakest. Horizontal heat advection provides warming during boreal summer and fall, when southwestward surface currents and horizontal SST gradients are strongest, and is close to zero during the remainder of the year. Vertical turbulent mixing, estimated as a residual in the heat balance, also undergoes a significant seasonal cycle. Cooling from this term is strongest in boreal summer, when surface wind and buoyancy forcing are strongest, the thermocline ridge is shallow (<90 m), and the mixed layer is deepening. These empirical results provide a framework for addressing intraseasonal and interannual climate variations, which are dynamically linked to the seasonal cycle, in the southwestern tropical Indian Ocean. They also provide a quantitative basis for assessing the accuracy of numerical ocean model simulations in the region.


2016 ◽  
Vol 29 (6) ◽  
pp. 2095-2108 ◽  
Author(s):  
Wenting Hu ◽  
Renguang Wu

Abstract The study analyzes precipitation variability and related air–sea interaction processes over the South China Sea (SCS) and tropical Indian Ocean (TIO) during the spring-to-summer transition season. It is found that physical processes are very different for the variations of seasonal mean and the monthly departures from the seasonal mean. Corresponding to the seasonal mean anomaly, remote forcing from the equatorial Pacific is a major factor for the precipitation variability with a prominent negative feedback of the atmosphere on the ocean. However, from the viewpoint of the monthly anomaly departure from the seasonal mean, a pronounced local coupled air–sea interaction is detected in both the SCS and TIO that features a sequential process of less rainfall, higher sea surface temperature (SST), more rainfall, and lower SST. The evolution of the SST tendency is well coordinated with that of net surface heat flux in the SCS and TIO. During the transition season, shortwave radiation is a dominant term for the SST change in the SCS, whereas both shortwave radiation and latent heat flux are responsible for the SST change in the TIO. The local air–sea relationship shows an obvious spatiotemporal variation during the transition season. Furthermore, the SST anomaly departure in the TIO (SCS) in April (May) could be considered as an indicator for local precipitation anomaly departure in May (June).


2013 ◽  
Vol 20 (3) ◽  
pp. 660-671 ◽  
Author(s):  
Xuezhong CHEN ◽  
Shenglong YANG ◽  
Yu Zhang ◽  
Wei FAN ◽  
Yumei WU

2012 ◽  
Vol 40 (3-4) ◽  
pp. 743-759 ◽  
Author(s):  
M. G. Keerthi ◽  
M. Lengaigne ◽  
J. Vialard ◽  
C. de Boyer Montégut ◽  
P. M. Muraleedharan

2021 ◽  
Vol 95 (2) ◽  
Author(s):  
Shiva Shankar Manche ◽  
Rabindra K. Nayak ◽  
Prakash Chandra Mohanty ◽  
M. V. R. Shesasai ◽  
V. K. Dadhwal

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 849
Author(s):  
Hyun-Ju Lee ◽  
Emilia-Kyung Jin

The global impact of the tropical Indian Ocean and the Western Pacific (IOWP) is expected to increase in the future because this area has been continuously warming due to global warming; however, the impact of the IOWP forcing on West Antarctica has not been clearly revealed. Recently, ice loss in West Antarctica has been accelerated due to the basal melting of ice shelves. This study examines the characteristics and formation mechanisms of the teleconnection between the IOWP and West Antarctica for each season using the Rossby wave theory. To explicitly understand the role of the background flow in the teleconnection process, we conduct linear baroclinic model (LBM) simulations in which the background flow is initialized differently depending on the season. During JJA/SON, the barotropic Rossby wave generated by the IOWP forcing propagates into the Southern Hemisphere through the climatological northerly wind and arrives in West Antarctica; meanwhile, during DJF/MAM, the wave can hardly penetrate the tropical region. This indicates that during the Austral winter and spring, the IOWP forcing and IOWP-region variabilities such as the Indian Ocean Dipole (IOD) and Indian Ocean Basin (IOB) modes should paid more attention to in order to investigate the ice change in West Antarctica.


Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 543
Author(s):  
Dai ◽  
Cheng ◽  
Goto ◽  
Schutgens ◽  
Kikuchi ◽  
...  

We present the inversions (back-calculations or optimizations) of dust emissions for a severe winter dust event over East Asia in November 2016. The inversion system based on a fixed-lag ensemble Kalman smoother is newly implemented in the Weather Research and Forecasting model and is coupled with Chemistry (WRF-Chem). The assimilated observations are the hourly aerosol optical depths (AODs) from the next-generation geostationary satellite Himawari-8. The posterior total dust emissions (2.59 Tg) for this event are 3.8 times higher than the priori total dust emissions (0.68 Tg) during 25–27 November 2016. The net result is that the simulated aerosol horizontal and vertical distributions are both in better agreement with the assimilated Himawari-8 observations and independent observations from the ground-based AErosol RObotic NETwork (AERONET), the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). The developed emission inversion approach, combined with the geostationary satellite observations, can be very helpful for properly estimating the Asian dust emissions.


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