caa a22 4500 605473331 CHVBK 20210128100342.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00382-014-2178-5 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2178-5 Modeling winter rainfall in Northwest India using a hidden Markov model: understanding occurrence of different states and their dynamical connections [Elektronische Daten] [Indrani Pal, Andrew Robertson, Upmanu Lall, Mark Cane] A multiscale-modeling framework for daily rainfall is considered and diagnostic results are presented for an application to the winter season in Northwest India. The daily rainfall process is considered to follow a hidden Markov model (HMM), with the hidden states assumed to be an unknown random function of slowly varying climatic modulation of the winter jet stream and moisture transport dynamics. The data used are from 14 stations over Satluj River basin in winter (December-January-February-March). The period considered is 1977/78-2005/06. The HMM identifies four discrete weather states, which are used to describe daily rainfall variability over study region. Each state was found to be associated with a distinct atmospheric circulation pattern, with the driest and drier states, State 1 and 2 respectively, characterized by a lack of synoptic wave activity. In contrast, the wetter and wettest states, States 3 and 4 respectively, are characterized by a zonally oriented wave train extending across Eurasia between 20N and 40N, identified with ‘western disturbances' (WD). The occurrence of State 4 is strongly conditioned by the El Nino and Indian Ocean Dipole (IOD) phenomena in winter, which is demonstrated using large-scale correlation maps based on mean sea level pressure and sea surface temperature. This suggests that there is a tendency of higher frequency of the wet days and intense WD activities in winter during El Nino and positive IOD years. These findings, derived from daily rainfall station records, help clarify the sequence of Northern Hemisphere mid-latitude storms bringing winter rainfall over Northwest India, and their association with potentially predictable low frequency modes on seasonal time scales and longer. Springer-Verlag Berlin Heidelberg, 2014 Winter precipitation nationallicence Northwest India nationallicence Diagnostics nationallicence Western disturbances nationallicence Pal Indrani Department of Civil Engineering, College of Engineering and Applied Science, University of Colorado Denver, 1200 Larimer Street, Campus Box 116, 80204, Denver, CO, USA aut Robertson Andrew International Research Institute for Climate and Society (IRI), The Earth Institute at Columbia University, 10964, Palisades, NY, USA aut Lall Upmanu Department of Earth and Environmental Engineering, Columbia University, 10027, New York, NY, USA aut Cane Mark Lamont-Doherty Earth Observatory, Columbia University, 10964, Palisades, NY, USA aut Climate Dynamics Springer Berlin Heidelberg 44/3-4(2015-02-01), 1003-1015 0930-7575 44:3-4<1003 2015 44 382 https://doi.org/10.1007/s00382-014-2178-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2178-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pal Indrani Department of Civil Engineering, College of Engineering and Applied Science, University of Colorado Denver, 1200 Larimer Street, Campus Box 116, 80204, Denver, CO, USA aut NATIONALLICENCE 700 1- Robertson Andrew International Research Institute for Climate and Society (IRI), The Earth Institute at Columbia University, 10964, Palisades, NY, USA aut NATIONALLICENCE 700 1- Lall Upmanu Department of Earth and Environmental Engineering, Columbia University, 10027, New York, NY, USA aut NATIONALLICENCE 700 1- Cane Mark Lamont-Doherty Earth Observatory, Columbia University, 10964, Palisades, NY, USA aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/3-4(2015-02-01), 1003-1015 0930-7575 44:3-4<1003 2015 44 382