scholarly journals Use of scatterometer based surface vorticity fields in forecasting genesis of tropical cyclones over the north Indian Ocean

MAUSAM ◽  
2021 ◽  
Vol 62 (1) ◽  
pp. 61-72
Author(s):  
O. P. SINGH ◽  
HARVIR SINGH
Keyword(s):  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lead Time ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
North Indian Ocean ◽  
The North ◽  
Peak Intensity ◽  
Ocean Surface Wind ◽  
Vorticity Anomaly

. Utilizing surface vorticity fields computed with the ocean surface wind speed and direction dataobtained from QuikSCAT, a study has been undertaken to investigate the increase in surface vorticity during the genesisphase of tropical cyclones over the north Indian Ocean. Six named tropical cyclones; Agni, Hibaru, Mala, Akash, Nargisand Phyan which formed over the region during 2004-2009 have been selected for this purpose. It has been found thatthere was a steep rise in scatterometer based surface vorticity before the formation of a cyclone in the cyclogenesisregion. The peak surface vorticity in the genesis region was observed on the day of intensification of the vortex to thedepression stage or a day earlier. However, the rising trend in the genesis region begins a few days before the formationof the system. Thus, the surface vorticity fields derived on the basis of scatterometer data can provide predictiveindication of the genesis of tropical cyclones over the Bay of Bengal and Arabian Sea with a lead time of 2-3 days. Usingthis technique it is possible to increase the lead time of pre-cyclone watch period over the north Indian Ocean. No relationship was found between the peak surface vorticity anomaly during the genesis phase and the surfacevorticity anomaly at the time of peak intensity of the system during its life cycle. In other words, the peak surfacevorticity anomaly during genesis phase does not provide any indication of future maximum intensity of the cyclone.

Extended Prediction of North Indian Ocean Tropical Cyclones

2012 ◽  
Vol 27 (3) ◽  
pp. 757-769 ◽  
Author(s):  
James I. Belanger ◽  
Peter J. Webster ◽  
Judith A. Curry ◽  
Mark T. Jelinek
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
North Indian Ocean ◽  
Ensemble Prediction ◽  
Tropical Cyclone Genesis ◽  
Lead Times ◽  
Prediction System ◽  
Ensemble Prediction System ◽  
The North

Abstract This analysis examines the predictability of several key forecasting parameters using the ECMWF Variable Ensemble Prediction System (VarEPS) for tropical cyclones (TCs) in the North Indian Ocean (NIO) including tropical cyclone genesis, pregenesis and postgenesis track and intensity projections, and regional outlooks of tropical cyclone activity for the Arabian Sea and the Bay of Bengal. Based on the evaluation period from 2007 to 2010, the VarEPS TC genesis forecasts demonstrate low false-alarm rates and moderate to high probabilities of detection for lead times of 1–7 days. In addition, VarEPS pregenesis track forecasts on average perform better than VarEPS postgenesis forecasts through 120 h and feature a total track error growth of 41 n mi day−1. VarEPS provides superior postgenesis track forecasts for lead times greater than 12 h compared to other models, including the Met Office global model (UKMET), the Navy Operational Global Atmospheric Prediction System (NOGAPS), and the Global Forecasting System (GFS), and slightly lower track errors than the Joint Typhoon Warning Center. This paper concludes with a discussion of how VarEPS can provide much of this extended predictability within a probabilistic framework for the region.

scholarly journals Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lower Stratosphere ◽  
North Indian Ocean ◽  
Satellite Observations ◽  
Upper Troposphere ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

scholarly journals Impact of air-sea coupling on the simulation of tropical cyclones in the North Indian Ocean using a simple 3-D ocean model coupled to ARW

2016 ◽  
Vol 121 (16) ◽  
pp. 9400-9421 ◽  
Author(s):  
C. V. Srinivas ◽  
Greeshma M. Mohan ◽  
C. V. Naidu ◽  
R. Baskaran ◽  
B. Venkatraman
Keyword(s):  
Indian Ocean ◽  
Tropical Cyclones ◽  
Ocean Model ◽  
North Indian Ocean ◽  
The North
Sign in / Sign up

Export Citation Format

Share Document