EFFECT OF WESTWARD MOVING CLOUD ORGANISATIONS IN WEST AND NEAR EQUATORIAL PACIFIC OCEAN ON THE MONSOON RAINFALL OF INDIA

Th en: are various synoptic s)')leDls which affect the rainfall over India during southwest mansoonseason directly or indirectly. AJ'110 J12 them. one subject of interest is the westward movina cloud pulses over th eequatorial wt'sl Pacific region. An attempt h as been made to connect the satellite c10uJ pulses in the eq ua torial westPacific. ns seen in the INSAT· I geostationary satellite imageries. with the rai nfall of selected meteorological subqh·i~ on~ o f Ind ia v.tlkh an: seemingly affected by Ih ~'~ pulses.

Inter-basin interactions between the Pacific and Atlantic Oceans depending on the phase of Pacific decadal Oscillation and Atlantic multi-decadal oscillation

The authors investigated the inter-basin interactions between the Pacific and Atlantic Oceans depending on the phase relationship of Pacific decadal oscillation (PDO)/Atlantic multi-decadal oscillation (AMO) based on observations and idealized model experiments. When the AMO and the PDO are in-phase (i.e., +PDO/+AMO or −PDO/-AMO), the Pacific Ocean regulates the SST anomalies in the equatorial Atlantic Ocean with altering a Walker circulation. During this period, there is a negative SST-precipitation relationship in the equatorial Atlantic Ocean where the atmosphere forces the ocean. In contrast, when they are out-of-phase (i.e., either +PDO/-AMO or −PDO/+AMO), the Atlantic Ocean influences the equatorial Pacific Ocean by modifying Walker circulation, resulting in a westward shift of a center of convective forcing in the equatorial Pacific Ocean compared to that during an inphase relationship of PDO/AMO. During this period, a positive SST-precipitation relationship is dominant in the equatorial Atlantic Ocean where the ocean forces the atmosphere. To verify this result, we conducted pacemaker experiments using the Nanjing University of Information Science and Technology Earth System Model version 3 (NESM3). Model results supported our findings obtained from the observations. We infer that the characteristics of the Pacific-Atlantic inter-basin interactions depend on whether the PDO and AMO phases are either in-phase or out of phase.

ASSESSMENT OF POSSIBLE CHANGES IN THE EL NINO AND LA NINA REPEATABILITY BY THE END OF THE XXI CENTURY USING THE CMIP6 MODELS

The quality of SST anomalies revealed in the equatorial Pacific associated with El Niño (EN) and La Ni-ña (LN) in the CMIP6 project models (KIOST-ESM, MIROC-ES2L and INM-CM4-8) was evaluated by comparing with real events in the period 1950 to 2014 using the ERSSTv5 data sets. It is shown that the ensemble model estimation of the number, intensity and duration of EN and LN corresponds quite well to real conditions. On this basis, the corresponding model ensemble calculations of their future possible changes in 2021-2085 relative to the historical 1950-2014 period were carried out for two possible sce-narios: business-as-usual (SSP2-4.5) and negative (SSP5-8.5).