Observation Characteristics and Synoptic Mechanisms of Typhoon Lekima Extreme Rainfall in 2019

Fig  1.   The track of typhoon Lekima(the dot-line) with stations of extreme daily rainfall(the dot)(a) and the accumulated rainfall from 0800 BT 8 Aug to 0800 BT 14 Aug in 2019 (the shaded denotes rainfall over 100 mm)(b)

Fig  2.   Monitoring of short-term heavy rainfall in Zhejiang and Shandong from 8 Aug to 14 Aug in 2019

(a)Zhejiang area from 2000 BT 9 Aug to 2000 BT 10 Aug in 2019, (b)Shandong area from 2000 BT 10 Aug to 2000 BT 11 Aug in 2019, (c)hourly rainfall at Kuocangshan of Zhejiang, (d)hourly rainfall at Zichuan of Shandong

Fig  3.   500 hPa geopotential height(the contour, unit:dagpm) and 850 hPa wind (the barb denotes velocity no less than 6 m·s^-1, the shaded denotes the wind speed more than 20 m·s^-1, the red think line denotes trough line) at 2000 BT 9 Aug(a), 2000 BT 10 Aug(b), 2000 BT 11 Aug(c) in 2019

Fig  4.   The evolution of FY-2G TBB(below -52℃) with 3 h accumulated rainfall from 2300 BT 9 Aug to 0500 BT 10 Aug in 2019

Fig  5.   Cross-section of the moisture flux divergence(the contour, unit:10^-7 g·hPa^-1·cm^-2·s^-1) along the typhoon center at 2000 BT 9 Aug(a), 0200 BT 10 Aug(b), 0800 BT 10 Aug(c) in 2019 (the black triangle denotes the typhoon center, the black thick line denotes the location of extremely strong rainfall)

Fig  6.   Cross-section of vorticity(the shaded) and divergence velocity(the contour, unit:10^-5 s^-1) along the typhoon center at 2000 BT 9 Aug(a), 0200 BT 10 Aug(b), 0800 BT Aug(c) in 2019 (the black triangle denotes the typhoon center, the black thick line denotes the location of extremely strong rainfall)

Fig  7.   The wind field(the vector) at 0500 BT 10 Aug 2019 with terrain(the shaded) (the red vector denotes airflow, the red dashed line denotes convergence)(a) and cross-section of average vertical velocity(the shaded) in the east of Zhejiang(the blue box area showed in Fig. 7a)(b)

Fig  8.   Wind field and water vapor transfer on 11 Aug 2019

(a)850 hPa wind(the arrow, no less that 20 m·s^-1) and moisture flux(the shaded, unit:g·kg^-1·m·s^-1) at 0200 BT, (b)850 hPa wind(the arrow, no less that 20 m·s^-1) and moisture flux(the shaded, unit:g·kg^-1·m·s^-1) at 0800 BT, (c)925 hPa wind(the barb, no less than 12 m·s^-1) and moisture flux divergence(the shaded, unit:10^-7 g·kg^-1·m·s^-1) at 0200 BT, (d)925 hPa wind(the barb, no less than 12 m·s^-1) and moisture flux divergence (the shaded, unit:10^-7 g·kg^-1·m·s^-1) at 0800 BT

Fig  9.   Cross-section of positive vorticity(the shaded) and divergence(the contour, unit:10^-5 s^-1) along the typhoon center at 0200 BT(a) and 0800 BT(b) on 11 Aug 2019 with cross-section of θ_se (the red contour, unit:K) and meridional vertical velocity(the vector is the combination of meridional wind and vertical movement(multiplied by 100), the black contour denotes the area upward movement no more than -0.5×10^-2 Pa·s^-1) along the typhoon center at 0200 BT(c) and 0800 BT(d) on 11 Aug 2019(the black triangle denotes the location of typhoon center, the black thick line denotes the location of extremely strong rainfall)

Fig  10.   Combined reflectivity factors(the shaded) at 2100 BT 10 Aug(a), 0100 BT 11 Aug(b) and 0500 BT 11 Aug(c) in 2019(the black dot denotes the typhoon center)

Fig  11.   The surface wind(the vector) at 0200 BT 11 Aug 2019 with terrain(the shaded)

Fig  12.   Cross-section of θ_se(the red contour, unit:K) and zonal vertical velocity(the vector is the combination of zonal wind and vertical movement(multiplied by 100), the black contour denotes the upward movement no more than -0.2×10^-2 Pa·s^-1)) along the typhoon center at 2000 BT 11 Aug(a), 0200 BT 12 Aug(b), 0800 BT 12 Aug(c) in 2019 (the brown dotted line denotes θ_se front area, the blue arrow denotes dry cold invasion)