Further investigation on stratospheric air intrusion into the troposphere during the episode of tropical cyclone: Numerical simulation and MST radar observations

Influence of tropical cyclones on tropospheric ozone: possible implications

“…Das et al (2011) and Pan et al (2015) have shown the ability of WRF simulations during a tropical cyclone. Figure 5 shows the height-time cross section of (a) vertical velocity along with potential vorticity (magenta line) and potential temperature (black line) contours, and (b) relative humidity along with equivalent potential temperature (black line) and zonal wind (grey line) for Nilam (left panels) and Phailin (right panels) over Trivandrum using WRF simulations.…”

“…Appenzeller and Davies (1992) have also discussed that exchange between the stratosphere and the troposphere (both directions) is highly episodic. There is much observational evidence supporting the slow intrusion of stratospheric air into the troposphere during cutoff lows (Vaughan and Price, 1989), high/low-pressure systems (Davies and Schuepbach, 1994), the tropopause folds and in a rapid episodic manner which is generally triggered by overshooting convections, such as tropical cyclones (Loring Jr. et al, 1996;Baray et al, 1999;Cairo et al, 2008;Das, 2009;Das et al, 2011;Zhan and Wang, 2012;Jiang et al, 2015;Venkat Ratnam et al, 2016). Overshooting convections associated with tropical cyclones can weaken the tropopause stability, which plays a key role in the stratosphere-troposphere exchange.…”

“…A recent study by Pan et al (2015) has shown the enhancement of tropospheric ozone associated with the thunderstorm event. Subsidence of stratospheric air is generally observed in the vicinity of the cyclone (Appenzeller and Davies, 1992;Baray et al, 1999;Cairo et al, 2008;Leclair De Bellevue et al, 2006Das, 2009;Das et al, 2011;Venkat Ratnam et al, 2016). Slow stratospheric intrusion is reasonably well understood and is a regular phenomenon, whereas rapid intrusion needs to be understood in detail.…”

Applications of Mesoscale Atmospheric Models in Short-Range Weather Predictions During Satellite Launch Campaigns in India

“…On the other hand, the period of October to December is considered as post-monsoon season, when SHAR experiences frequent rainfall amounting from 75 to 100 cms, almost an order larger than that observed during the pre-monsoon season. SHAR being one of the coastal stations on the eastern coastline of the Indian subcontinent very well falls in the vicinity of tropical cyclone landfall zone (Das et al, 2011;Rakesh et al, 2007;Singh et al, 2005), and therefore it is obvious that the underlying complex terrain could very well affect the local winds, resulting at times in the developments of hazardous thunderstorms. The depressions that develop over the Bay of Bengal can also affect the short-term weather of SHAR.…”

Ozone trends in the vertical structure of Upper Troposphere and Lower stratosphere over the Indian monsoon region

“…For example, transport of boundary layer air into lower stratosphere due to strong Summer monsoon convection (Park et al 2009;Goswami et al 2006;Kunze et al 2010;Randel et al 2010;Chen et al 2012). Stratospheric intrusion during Winter and early pre-monsoon season (Fadnavis et al 2010) and cyclonic activity during premonsoon and post-monsoon seasons (Das et al 2011;Baray et al 1999;Sigmond et al 2000 The SAGE II data used here are based on the v6.2 retrieval algorithm. SAGE II is a solar occultation instrument where measurements are only made during limb viewing conditions providing 15 sunrise and 15 sunset measurements per day.…”