Expert of the Week   for  26 Oct - 01 Nov 2015

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Somnath Jha

Deputy Supdt. of Police

Department of Home, Govt. of West Bengal, India Expertise:  More than seven years experience in Numerical Climate Simulation with special reference to regional climate simulation to study the monsoon meteorology. More than five years of experience in Crop Simulation Modeling to investigate various sensitivity studies of impact on crop yield. Experience in Risk Modeling for weather based risk product development.

Somnath Jha completed his Masters of Science in Agricultural Physics from Indian agricultural Research Institute (IARI), New Delhi, India from 2003-2005; he completed his PhD in Atmospheric Sciences from Indian Institute of Technology, Delhi, India in 2012; he served as Senior Modeler in Risk Management Solutions Inc., Newark, CA from 2010 to 2013; he served as Deputy Magistrate & Deputy Collector, Govt. of West Bengal, India between 2013 to 2015; he joined as Deputy Supdt. of Police, Department of Home Department, Govt. of West Bengal, India in June, 2015. He has contributed many journal papers, presentation, conferences and delivered lecture, lead talk and guest lectures in Indian Meteorological Society, Indian Council of Agricultural Research (ICAR), New Delhi, India; Administrative Training Institute, West Bengal; Micro-Insurance Round Table Conference (MiRT), NTU, Singapore etc . He cherished a rare experience of cross-disciplinary angle across science, corporate, civil services towards the climate-agriculture-food insecurity aspects.

‘New Normal’ Weather Emerging as a Potential Driver of Socio-Economic Quake

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QQuestion by Dr Mourani Sinha

Dear Dr. Jha,
Its true that the 'new normal' weather events are frequenting during the recent decade. We all have seen the category 5 "Hurricane Patricia" last week in Mexico and its unprecedented nature. How this "new normal" weather is affecting the global ocean dynamics and how can we tune up the available wind wave model or make these robust enough to accommodate the risk of new normals?

Dr Mourani Sinha Assistant Professor | Techno India University, India

APosted on 01 Nov 2015

Dr. Sinha,

Thank you for the question. 

I would like to say that it's probably the ocean which is acting like a heat reservoirs of our earth. The energy is being reserved in ocean and the ocean itself is being act like energy source. Thus, new normals in weather and climate exerts perturbation onto the oceanic column of water. But the perturbation by weather is buffered by the long memory of the ocean with gradually shifting the mean energy state of the global ocean. This is also affecting gradually the surface current dynamics of global ocean. This may gradually change the ekman current and ekman mass transport in the ocean too. The possible change of oceanic circulation and or mean energy state would result due to this new normals. Changing weak relationship between global teleconnection parameter and regional weather bears the testimony to it. Thus it would affect  global circulation pattern. 

Wind wave model generally uses wind as a major input variable to this. We need to find satellite based wind variable or a secondary remote sensing variable which can easily be representative of the wind variable. This high spatio-temporal variable be used as input to the wind wave model. The model dynamics and physics core be updated as per the region. Thus we can reduce the model or forecast error to a considerable level. Besides, the new process dynamics of ocean be integrated into the model. Thus, it can be used for oceanic wind wave model.

QQuestion by Mr Dave Paul Zervaas

Dear Somnath, you mention that climatic uncertainty has become the ‘new normal’ across the globe. In yr view, how can we model this uncertainty into new models and still get meaningful forecasts that can help to plan for adequate agricultural strategies in, for instance, India. Or do you think we just have to accept that 'chaotic behavior' or uncertainty will render models less reliable? Thks

Mr Dave Paul Zervaas Programme Officer | UNISDR

APosted on 01 Nov 2015

Mr. Dave,

Thank you for the hit question. Yes, it is true that climatic uncertainty has become the new normal. You see, the hurricane Patricia which lashed in Mexico last week was a surprise in respect of nature and characteristics.But it is not acceptable that we would continue to accept this new normal play havoc on us. We have to redesign our model architecture in a way that the associated risk out of those uncertainties be well represented. While doing so, we need to address the following;

Statistical models built out of longterm historical data and on the basis of  probabilistic assumptions may likely to be affected. Generally,  multi-model ensemble is generally used to overcome the limitation of various model and reduce model error and uncertainties. But this initiative may not be sufficient. We should remember that the forecast out of probabilistic models are limited by the statistics of fed historical timeseries data which with the progression of time and occurrence of new normal events proves less representative day by day. On the other hand, the numerical models generally provides the forecast output based on the limitation of assumptions in its model physics and dynamics. The numerical weather or climate model physics, dynamics are developed primarily based on temperate regime. Therefore, many efficient model lacks its approximate representative tropical model physics and dynamics and thus add up a high systematic bias, which becomes very difficult to ameliorate later on, due to forecast based on this. Therefore, model physics and dynamics have to be relooked once based on the regional application and model assumptions. Realistic good satellite based predictor variables are required to be identified for the model physics and dynamics so that high spatio-temporal resolution model input data be fed to the region specific model. Satellite data assimilation into the dynamic or numerical model has already been progressed a lot. But there is a need to relook into the tropical region specific model physics and dynamics. The identification of oceanic component in new normal should also be relooked into. The new normal are affecting the ocean also. Or in other way, we can say that the exposure of new normals on the ocean which have a long memory may gradually affect the oceanic dynamics in very different way. This is also being reflected in finding the weak global teleconnection to the regional weather now-a-days. For example, the relationship between ENSO activity and regional and local precipitation is decaying day by day. Most of the global numerical models are built generally strongly as a robust AGCM with nearly no representation of this global teleconnectivity parameter. This has a deep bearing in the model efficiency in predicting the new normals. Thus, we can relook into the issue of new normals in weather and finetune the available models, developing or modifying the associated model physics and dynamics, assimilating the satellite input variable and minimize the model error in forecasting the new normals and come up with a reasonable agricultural strategy for a tropical country like India.