Rainfall Assimilation through an Optimal Control of Initial and Boundary Conditions in a Limited-Area Mesoscale Model

1996 ◽  
Vol 124 (12) ◽  
pp. 2859-2882 ◽  
Author(s):  
X. Zou ◽  
Y-H. Kuo
2011 ◽  
Vol 29 (7) ◽  
pp. 1295-1303 ◽  
Author(s):  
I. Soltanzadeh ◽  
M. Azadi ◽  
G. A. Vakili

Abstract. Using Bayesian Model Averaging (BMA), an attempt was made to obtain calibrated probabilistic numerical forecasts of 2-m temperature over Iran. The ensemble employs three limited area models (WRF, MM5 and HRM), with WRF used with five different configurations. Initial and boundary conditions for MM5 and WRF are obtained from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) and for HRM the initial and boundary conditions come from analysis of Global Model Europe (GME) of the German Weather Service. The resulting ensemble of seven members was run for a period of 6 months (from December 2008 to May 2009) over Iran. The 48-h raw ensemble outputs were calibrated using BMA technique for 120 days using a 40 days training sample of forecasts and relative verification data. The calibrated probabilistic forecasts were assessed using rank histogram and attribute diagrams. Results showed that application of BMA improved the reliability of the raw ensemble. Using the weighted ensemble mean forecast as a deterministic forecast it was found that the deterministic-style BMA forecasts performed usually better than the best member's deterministic forecast.


2017 ◽  
Vol 30 (15) ◽  
pp. 6017-6036 ◽  
Author(s):  
Sachie Kanada ◽  
Tetsuya Takemi ◽  
Masaya Kato ◽  
Shota Yamasaki ◽  
Hironori Fudeyasu ◽  
...  

Intense tropical cyclones (TCs) sometimes cause huge disasters, so it is imperative to explore the impacts of climate change on such TCs. Therefore, the authors conducted numerical simulations of the most destructive historical TC in Japanese history, Typhoon Vera (1959), in the current climate and a global warming climate. The authors used four nonhydrostatic models with a horizontal resolution of 5 km: the cloud-resolving storm simulator, the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model, the Japan Meteorological Agency (JMA) operational nonhydrostatic mesoscale model, and the Weather Research and Forecasting Model. Initial and boundary conditions for the control simulation were provided by the Japanese 55-year Reanalysis dataset. Changes between the periods of 1979–2003 and 2075–99 were estimated from climate runs of a 20-km-mesh atmospheric general circulation model, and these changes were added to the initial and boundary conditions of the control simulation to produce the future climate conditions. Although the representation of inner-core structures varies largely between the models, all models project an increase in the maximum intensity of future typhoons. It is found that structural changes only appeared around the storm center with sudden changes in precipitation and near-surface wind speeds as the radius of maximum wind speed (RMW) contracted. In the future climate, the water vapor mixing ratio in the lower troposphere increased by 3–4 g kg−1. The increased water vapor allowed the eyewall updrafts to form continuously inside the RMW and contributed to rapid condensation in the taller and more intense updrafts.


MAUSAM ◽  
2021 ◽  
Vol 57 (1) ◽  
pp. 129-134
Author(s):  
R. G. ASHRIT ◽  
M. DAS GUPTA ◽  
A. K. BOHRA

lkj & bl v/;;u esa 29 vDrwcj] 1999 dks mM+hlk ds rV ij vk, egkpØokr ds izfr:i.k ds fy, ,u- lh- ,- vkj@ih- ,l- ;w-  ,e- ,e- 5 eslksLdsy fun’kZ ¼xzsy bR;kfn 1995½ dk mi;ksx fd;k x;k gsA bl fun’kZ esa pØokr dh izkjafHkd voLFkk vkSj mldh ifjlhekvksa dh voLFkkvksa ds :i  esa jk"Vªh; e/;&vof/k ekSle iwokZuqeku dsUnz Vh- 80 ds izpkyukRed fo’ys"k.kksa dk iz;ksx fd;k x;k gS vkSj rwQku dh vof/k esa 3 fnu rd dk iwokZuqeku rS;kj djus ds fy, bl fun’kZ dks 72 ?kaVs dh vof/k ds fy, lekdfyr fd;k x;k gSA bl v/;;u dk mn~ns’; pØokr ds ekxZ ij dfYir Hkzfey ds izHkko dk ewY;kadu djuk vkSj pØokr dh rhozrk dk iwokZuqeku yxkuk gSA In this study NCAR/PSU MM5 mesoscale model (Grell et al. 1995) is used to simulate the super cyclone that struck the Orissa coast on 29th October 1999. The model makes use of the operational NCMRWF T 80 analysis as initial and boundary conditions and is integrated up to 72 hr for producing 3-day forecast of the storm. The aim of this study is to assess the impact of bogus vortex on track and intensity prediction. 


1971 ◽  
Vol 2 (3) ◽  
pp. 146-166 ◽  
Author(s):  
DAVID A. WOOLHISER

Physically-based, deterministic models, are considered in this paper. Physically-based, in that the models have a theoretical structure based primarily on the laws of conservation of mass, energy, or momentum; deterministic in the sense that when initial and boundary conditions and inputs are specified, the output is known with certainty. This type of model attempts to describe the structure of a particular hydrologic process and is therefore helpful in predicting what will happen when some change occurs in the system.


2021 ◽  
pp. 1-21
Author(s):  
Claudia Gariboldi ◽  
Takéo Takahashi

We consider an optimal control problem for the Navier–Stokes system with Navier slip boundary conditions. We denote by α the friction coefficient and we analyze the asymptotic behavior of such a problem as α → ∞. More precisely, we prove that if we take an optimal control for each α, then there exists a sequence of optimal controls converging to an optimal control of the same optimal control problem for the Navier–Stokes system with the Dirichlet boundary condition. We also show the convergence of the corresponding direct and adjoint states.


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