Asymmetry in space-time characteristics of Indian summer monsoon intraseasonal oscillations during extreme years: Role of seasonal mean state

2014 ◽  
Vol 35 (8) ◽  
pp. 1948-1963 ◽  
Author(s):  
S. Sharmila ◽  
S. Joseph ◽  
R. Chattopadhyay ◽  
A. K. Sahai ◽  
B. N. Goswami
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Space Time ◽  
Intraseasonal Oscillations ◽  
Mean State

scholarly journals Study of the microphysical properties associated with the Monsoon Intraseasonal Oscillation as seen from the TRMM observations

2012 ◽  
Vol 30 (6) ◽  
pp. 897-910 ◽  
Author(s):  
M. Halder ◽  
P. Mukhopadhyay ◽  
S. Halder
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Liquid Water ◽  
Tropical Rainfall Measuring Mission ◽  
Cloud Water ◽  
Cloud Liquid Water ◽  
Tropical Rainfall ◽  
Intraseasonal Oscillations ◽  
Cloud Ice

Abstract. The spatio-temporal variability of Indian Summer Monsoon is well studied based on different types of rainfall data. However, very few attempts have been made to study the underlying role of clouds and its hydrometeors on Monsoon Intraseasonal Oscillations. The northward propagating Monsoon Intraseasonal Oscillations and its characteristics remain a challenge for the numerical modelers even today. In view of this, we have set out to analyze the role of cloud hydrometeors and their linkage with northward propagating Monsoon Intraseasonal Oscillations. The science question that we intend to address here is whether the different phases of the cloud hydrometeors show similar propagation characteristics as that of rainfall, and what are the relations of their phases with the convection centre using Tropical Rainfall Measuring Mission data. In answering the question, we have analyzed ten years of Tropical Rainfall Measuring Mission 2A12 hydrometeor data over Indian region. Our analyses show that the cloud water and cloud ice do show a large scale organization during the Indian Summer Monsoon regime of June–September, and systematically progress northward getting initiated over equatorial Indian Ocean. On further analyses, we found that cloud water actually leads the rainfall and cloud ice lags the rainfall. We have further demonstrated the process by analyzing dynamical parameters from Modern Era-Retrospective Analysis for Research and Applications. The presence of cloud water in the lower troposphere in the leading edge of rainfall indicates the lower level moistening and preconditioning of the convective instability due to enhanced moisture convergence. Subsequently, deep convection is triggered, which generates hydrometeor above freezing level and cloud ice in the upper troposphere. To quantify objectively the relation among cloud liquid water, cloud ice and rainfall, the lag correlation is computed with respect to convection center, where the above hypothesis is established that cloud liquid water leads the rainfall and cloud ice lag. This relation among hydrometeors may help the numerical modelers to incorporate such processes for capturing the characteristics of Monsoon Intraseasonal Oscillations.

scholarly journals The role of potential vorticity anomalies in the Somali Jet on Indian Summer Monsoon Intraseasonal Variability

2017 ◽  
Vol 50 (11-12) ◽  
pp. 4149-4169 ◽  
Author(s):  
P. Rai ◽  
M. Joshi ◽  
A. P. Dimri ◽  
A. G. Turner
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Potential Vorticity ◽  
Intraseasonal Variability ◽  
Somali Jet
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