Analysis of rananim using ATOVS retrieval products Liu zhe[1] Han zhigang[2] Zhao zengliang[2] Zhang fengying[3] 1. Institute of Meteorology, PLA University of Science and Technology, Naning, 2.Beijing Institute of Applied Meteorology, Beijing, China 3. National Satellite Meteorology Center, Beijing, China

Seen from GOES-9 image, rananim shows Background a well-developed broad central dense overcast (CDO) and a clear , several The number 0414 typhoon rananim has caused serious damage to part of the districts in province of China. In this paper, the thermal spiral bandings kept transporting water structure and intensity of rananim was analyzed by the products of vapor from the warm sea to strengthen its temperature and humidity profiles retrieved from ATOVS. intensity. AMSU-B 150GHz window channel has the ability to sense precipitation-sized particles through the CDO because its A portion of the ATOVS retrieval products swath sensitivity to precipitation causes greater Infrared image of GOES-9 AMSU-B 150GHz image of NOAA-16 (*T was the central position of typhoon rananim) contrast between the eye and eyewall The maximum temperature anomaly is about Method 7k at 300hPa, the warm anomaly extending down into the lower troposphere at about First of all, determine the domain of typhoon center cloud field 500hPa inside the eye. What’s more, under according to the coincident infrared image. 600hPa pressure level, there appear • Introduction: Thermal structure negative temperature anomalies, which were Certain wavelengths of microwave energy are able to caused by heavy precipitation contamination. penetrate ice clouds (such as the cirrus above the storm). Temperature anomalies were calculated by subtracting the On the other hand, this contamination Therefore, it offers a unique perspective into average temperature of outer radius from the temperature at provides us useful information on the location structure. each grid in the domain The cross section of temperature anomalies and intensity of precipitation. Kidder et al (1978) first attempted passive microwave in The minimal sea level pressure With low-level cyclonic flow and an upper- monitoring tropical cyclone intensity estimation using ATOVS retrieval temperatures at 23 levels from 920 to 50hPa level anticyclone, the basic structure of SCAMS aboard Nimbus-5 and Nimbus-6 satellites. ATOVS retrieval temperatures at 23 levels from 920 to 50hPa were used to calculated the MSLP typhoon rananim’s tangential wind field Velden and Smith (1983) using MSU data to estimate the seems reasonable. However, the flow The virtual temperature effects were considered under the intensity and central pressure, They derived a set of linear The virtual temperature effects were considered under the becomes anticyclonic in the low levels near regression coefficients that related observed brightness 500hPa pressure level the eyewall. This phenomenon is probably temperature anomalies with aircraft observed minimum sea A two-pass distance-weighted analysis method (Barnes, 1964) due to the unrealistic cold anomalies level pressure(MSLP). was applied to interpolate the unevenly spaced temperature to a caused by the strong precipitation Cross-section of Tangential wind Removed low-level cold anomalies Kidder et al (2000) using the retrieved data from AMSU analyzed radial grid with the origin at the typhoon center attenuation near the eyewall under 5km. the upper tropospheric thermal anomalies; they also calculated the According to the method introduced by gradient winds from the temperature profiles. The hydrostatic equation was integrated at the outer radius of kidder(2000), the temperature anomalies at the domain by using NCEP reanalyzed data as initial parameter up Brueske (2001) developed a method to explicitly account for pressure levels between the surface and to the 50hPa level, then the equation was downward from 50 to subsampling and diffraction effects. 500hPa were set to zero and the gradient surface in the center grid By using the International ATOVS Processing Package (IAPP) by winds were recalculated. The tangential Cooperative Institute of Meteorological Satellite Studies (CIMSS) of The gradient wind field in any height wind at large radius appears more the University of Wisconsin (UW), the ATOVS data can be finally reasonable. However, the MSW was down Assuming a linear variation in temperature with height between translated into the retrieval products including the atmospheric to 39m/s. Thus, other methods should be two pressure levels to calculate the temperature and pressure as a temperature profile, moisture profile etc. developed to address the problem. Tangential wind fields of different height function of height at any height from surface to the tropopause ATOVS temperature and dew-point soundings were retrieved at Because the area range of ATOVS 42 vertical levels from 0.1 to 1000hPa. Calculate the density at each grid with ideal gas equation Result data received by National Satellite The root mean square (rms) differences between ATOVS retrieval According to the gradient assumption, the radial pressure Meteorology Center are not wide temperature profiles and radiosonde observation profiles are less gradients was to calculate the tangential wind at any height s enough, After mapping the area than 2k and 2.5k when under the clear and cloudy weather range of ATOVS retrieval data

)

) k with rananim tracks from CMS,

( respectively. As to dew-point profiles, the rms error is about 3.0- k

(

Case study £ y £© y we got four ideal sets of ATOVS m/s ¨

6.0k. hPa ¨ £ This set of ATOVS retrieval data we selected began at £ . anomal anomal retrieval data. p p MSW MSW Data 0546UTC on 12 Aug,2004. By interpolating the 3-hourly MSLP The MSLP and MSW was Max tem Max interval position and strength from the typhoon reporting tem Max. Although the cross-track-scanning ATOVS retrieval calculated respectively and of Center Meteorology Station(CMS), we got the central products swaths are about 2200km wide, the sample was compared with the typhoon limited to those cases in which the typhoon center fell position of rananim at that time was (27.2°N, 122.6°E), the

warning report of CMS, the mean MSLP was 950hPa and the maximum wind speed(MSW) near the center of ATOVS retrieval swaths such as the discrepancy was 11.8hPa and near eyewall was 45m/s, showing that rananim belongs to chart listed on the left. However, the chart listed on the 4.3m/s, showing similar time- ug 10 0000UTC 10 0000UTC ug 10 1800UTC ug Aug 11 0900UTC 0900UTC 11 Aug Aug 12 1500UTC Aug 12 0600UTC Aug 13 Aug 09 0000UTC 0000UTC 09 Aug Aug 12 0000UTC Aug 12 0000UTC A A Aug 10 1800UTC Aug 09 0000UTC Aug 11 0900UTC Aug 11 Aug 12 0000UTC Aug 13 0600UTC Aug 10 0000UTC right is not suit for research due to the coarse horizontal mature stage. Aug 12 1500UTC variant tendency of rananim as resolution MSLP and MWS calculated from ATOVS Compared with typhoon report described by CMS.