README for TiMREX Level 4 sonde data Updated: 30 November 2010 Author: Paul Ciesielski email: paulc@atmos.colostate.edu Notes: If multiple version exist of a data set, we recommend using the the latest version. For example, at 46750 a correction was done with CDF matching and Cady daytime (3.1 or 4.1), later a correction was done with VCC (vaisala provided corrected humidity coefficients) and Cady daytime (3.2 and 4.2). The versions 3.2 and 4.2 provide slightly improved comparison to independent TPW estimates. Some sites have mutiple sonde types: 46741 (76 ms80, 53 vs92) 46750 (248 vs80, 18 vs92) 46780 (201 vs80, 18 vs92) 46810 (156 ms80, 1 vs92) At 46741 and 46780, the different sonde types are at different times At 46750 and 46810, the different sondes types were used in an intercomparison study and thus are at same time. When the same time has two sonde types, we recommend using data from the more realiable vs92 sonde. Because the intercomparison studies (using graw, ms80 and vs92 sondes) at Banchiao were done in April and October (in non-monsoon conditions) and with a limited number of intercomparisons launches (12), the correction based on CDF matching is less than optimal for the Meisei and Graw sondes. Also the humidity sensors on the Mesei have little sensitivy at low humidities, thus the CDF correction was not applied to RH < 33% at these sites. The low-level thermodynamic data from the southwest ship (99810) appeared to be contaminated by the ship structure as evidenced by unreasonably large gradients in the temperature and moisture near the surface. A simple algorithm which identified the bad data and then extended the T and Td from the good data to the surface was implemented to remove this contamination problem. No additional humidity corrections were deemed necessary at the 99810. Laoag appeared to have a small dry bias so it was corrected using the CDF matching method with intercomparison data (vs92 and gra_w) collected at Banchiao. Cady - refers to daytime humidity correction for VS80 and VS92 sondes proposed in Cady-Pereira et al. (2008, JTECH). This correction is only a function of the solar zenith angle and is a constant in water vapor mixing ratio with height. Yoneyama - refers to daytime humidity correction for VS92 sondes proposed in Yoneyama et al. (2008, SOLA). This correction is a function of the solar zenith angle and increases in RH with height. The correction applied at each site was the one that provided the best validation with independent data (e.g., ground-based GPS or satellite derived PW). Updates: 06/22/2011: It was discovered that the lat/lon positions in 99810_4.1_vs92 were incorrectly switched. This was corrected in 99810_4.2_vs92 Reference: Ciesielski, P. E., W.-M. Chang, S.-C. Huang, R. H. Johnson, B. Jong-Dao Jou, W.-C. Lee, P.-H. Lin, C.-H. Liu, and J. Wang, 2010: Quality controlled upper-air sounding dataset for TiMREX/SoWMEX: Development and corrections. J. Atmos. Ocean. Tech., 27, 1802-1821. ***************************************************************************** File naming convention: stnid_Level_version_type where stnid is: station id Level 4: 5-hPa with QCflags Version # is: 0 - uncorrected humidity (applies to Levels 2 and 4) 1 to ? (various versions of correction, we recommend using highest version #) type: denotes sonde type (vs80 - vaisala 80, vs92 - vaisala 92 ms80 - meisei 80, graw) *** Level 4 (5hPa with qc flags) ********************************************** - in each file below individual sondes are combined into a single file in CSU format ("read_upa_L4.f", a fortran based program is provided to read Level 4 files) filename # sondes site type comment 46692_4.0_ms80 184 banchiao ms80 (no humidity correction) 46692_4.1_ms80 184 banchiao ms80 (CDF + Yoneyama daytime) 46699_4.0_vs80 185 hualien vs80 (no humidity correction) 46699_4.1_vs80 185 hualien vs80 (CDF + Cady daytime) 46734_4.0_vs80 232 makung vs80 (no humidity correction) 46734_4.1_vs80 232 makung vs80 (VCC + Cady daytime) 46741_4.0_ms80 76 tainan ms80 (no humidity correction) 46741_4.0_vs92 53 tainan vs92 (no humidity correction) 46741_4.1_ms80 76 tainan ms80 (CDF + Yoneyama daytime) 46741_4.1_vs92 53 tainan vs92 (Yoneyama daytime ) 46750_4.0_vs80 248 pingdong vs80 (no humidity corrections) 46750_4.0_vs92 18 pingdong vs92 (no humidity corrections) 46750_4.1_vs80 248 pingdong vs80 (CDF + Cady daytime) 46750_4.1_vs92 18 pingdong vs92 (Cady daytime) 46750_4.2_vs80 248 pingdong vs80 (VCC + Cady daytime) 46750_4.2_vs92 18 pingdong vs92 (Yoneyama daytime) 46780_4.0_vs80 201 lu-tao vs80 (no humidity corrections) 46780_4.0_vs92 18 lu-tao vs92 (no humidity corrections) 46780_4.1_vs80 201 lu-tao vs80 (VCC + Cady daytime) 46780_4.1_vs92 18 lu-tao vs92 (Yoneyama daytime) 46810_4.0_ms80 157 dongsha ms80 (no humidity corrections) 46810_4.1_ms80 157 dongsha ms80 (CDF + Yoneyama daytime) 46810_4.2_ms80 157 dongsha ms80 as 4.1 with additional qc for near sfc T and Td 98223_4.0_graw 67 laoag graw (no humidity corrections) 98223_4.1_graw 67 laoag graw (CDF + Yoneyama daytime) 99692_4.0_vs92 46 n. ship vs92 (no humidity corrections) 99692_4.1_vs92 46 n. ship vs92 (Yoneyama daytime) 99744_4.0_vs92 218 liou-guei vs92 (no humidity correctons) 99744_4.1_vs92 218 liou-guei vs92 (Yoneyama daytime) 99759_4.0_vs92 140 henchun vs92 (no humidity correctons) 99759_4.1_vs92 140 henchun vs92 (Yoneyama daytime) 99770_4.0_vs92 163 taichung vs92 (no humidity corrections) 99770_4.1_vs92 163 taichung vs92 (Yoneyama daytime) 99810_4.0_vs92 134 sw ship graw (no humidity corrections) 99810_4.1_vs92 134 sw ship graw (low-level T, Td correction), incorrect lat/lon 99810_4.2_vs92 134 sw ship graw (low-level T, Td correction), corrected lat/lon 99999_4.0_vs92 190 dropsonde vs92 (no humidity corrections)