Role of ocean–atmosphere interaction on northward propagation of Indian summer monsoon intra-seasonal oscillations (MISO)

Assessment of Madden–Julian oscillation simulations with various configurations of CESM

“…When the resolution is increased to 1° (CPL4_1d and CPL5_1d), the heating center slightly moves to the westerly wind, which enables energy accumulation and leads to wave instabilities. In short, the above lag-longitude and lag-latitude analyses reveal that the air-sea interaction and model resolution are both important for simulating the eastward propagation in the boreal winter, while the northward propagation in the boreal summer seem to be more sensitive to the atmosphere model (Sharmila et al 2013). This may suggest that the eastward propagation and northward propagation would have different mechanisms.…”

“…In addition, the MJO also shows northward propagation in the boreal summer (e.g., KemballCook and Wang 2001;Sharmila et al 2013). To extract the fundamental propagating and time-varying characteristics of the MJO, we calculate point-to-point correlation using the average intraseasonal OLR anomalies over the area of 10°S-5°N and 75°E-100°E as a reference, where the Fig.…”

What Controls Seasonal Evolution of Sea Surface Temperature in the Bay of Bengal? Mixed Layer Heat Budget Analysis Using Moored Buoy Observations Along 90°E

“…A slight SST variation in regions of high mean SST, particularly in basins like the BoB, can result in a strong atmospheric circulation response (Palmer and Mansfield, 1984). In order to forecast the spatiotemporal evolution of precipitation patterns over the Indian subcontinent and nearby landmass, it is imperative to represent BoB SST accurately in the oceanic component of coupled general circulation models Sharmila et al, 2013). In this paper, we use unique in situ observations and satellite data to examine some of the factors driving SST variability in the BoB.…”

Monsoons to Mixing in the Bay of Bengal: Multiscale Air-Sea Interactions and Monsoon Predictability

“…Thus, the prediction of seasonal mean monsoon rainfall one season in advance remains a challenging problem and makes prediction of MISO phases and their intensity a very attractive and useful alternative, even if those predictions can be made only two to three weeks in advance (Xavier and Goswami, 2007). Air-sea interactions over the BoB are at the heart of both the evolution and the northward propagation of MISOs Sharmila et al, 2013). These air-sea interactions are largely dominated by net heat flux variations at the surface, which are as large as 80-100 W m -2 into or out of the ocean (see Figure 2.18 of Goswami, 2012) and are associated with subseasonal changes in cloudiness and surface winds.…”

“…Thus, to improve MISO predictions, a model must accurately simulate variability in air-sea flux at multiple scales as well as air-sea interactions. While most coupled oceanatmosphere models still have difficulty simulating these MISO features (Sabeerali et al, 2013), some models such as the CFSv.2 (Coupled Forecast System model version 2 of the US National Centers for Environmental Prediction) are now able to simulate these MISO characteristics with some fidelity (Sabeerali et al, 2013;Sharmila et al, 2013). Using this opportunity, the Indian Institute of Tropical Meteorology (IITM), Pune, India, has set up an Extended Range Prediction System (ERPS) for forecasting MISOs.…”