Quality Control of OLYMPEX sounding data Steven Rutledge and Paul E. Ciesielski Colorado State University In this study on … OLYMPEX Workshop 21-23 March, 2017

Data was collected for the period 29 October to 16 January from 5 sites (red dots shown on map). In total 651 upsondes were collected and quality-controlled. At all sites, high vertical resolution (1-2s) data were collected except at CYZT (Port Hardy, BC) where only GTS resolution data were available. In addition, 53 dropsondes were launched from the NASA-DC8 platform.

Pertinent information for OLYMPEX sounding sites Station ID Sonde type Resolution # of soundings Port Hardy, BC 71109, CYZT VRS92 GTS 160 Env. Canada 99001, ENV 2 s 71 Quillayute, WA 72797, KUIL 1 s 162 NPOL-CSU 99000, NPOL 98 Salem, OR 72694, KSLE LMS Dropsondes 99002, DROP VRS904 0.25 s 53 Total 704 Black denotes operational sites, red are experiment enhanced sites VRS92 – Vaisala RS92 sonde with ground station running V3.64 software which include daytime heating and time-lag humidity corrections LMS – Lockheed Martin Sippican Mark II sonde

Visual inventory of sounding data each vertical line of dots represents a successful sonde launch Higher density of dots indicates periods with more frequent launches (up to 8/day at ENVC and NPOL) Quillayute (KUIL) took no soundings from 17 – 28 Dec. due to a power outage at this site. Quillayute went to 4/day soundings from 4-16 January.

Quality-control procedures Level 1 – data from all sites converted to a single ASCII format Level 2 – high-resolution data passed through a series of automated QC checks to systematically detect bad values. For this purpose we used ASPEN (Atmospheric Sounding Processing Environment), a software tool developed by NCAR EOL. This software removes bad data based on several QC checks (e.g., gross limit, vertical consistency, etc). Level 3 – sonde data are checked for humidity biases by comparing sonde TPW to collocated GPS TPW retrievals from SUOMINET data. Note: four of five sites used Vaisala RS sondes with software (V3.64) with built in humidity corrections. No humidity biases were found in the Vaisala data. No collocated GPS TPW were available to check the LMS sonde data from Salem, OR. Level 4 – user-friendly version of hi-res data was created (5-hPa resolution with QC flags on each variable which provide a measure of the data’s reliability). Convective parameters (CAPE, CIN, PW, LCL, EL etc.) computed when possible. Notes: all sites used GPS wind retrievals which have a stated accuracy of 0.15 m/s. all dropsondes were QC’d by NCAR EOL

Example of Level 3 Quality-Control Check on sonde humidity data (top) Mean diurnal cycle of TPW at KUIL with sonde data (green) and collocated GPS data (red) (bottom) mean PW difference (sonde – GPS); vertical lines are σ of this difference. Mean difference (0.07 mm) and difference at individual times (<0.5 mm) are well within uncertainty estimates of these instruments.

Sounding data availability Datasets for all levels were place on NASA Earthdata OLYMPEX archive. Datasets (Levels 2-4) are available in both ASCII and netcdf formats Datasets are available at: fcportal.nsstc.gov/olympex/get-data-ftp-server This site contains the following: - browse folder: skewt plots for all soundings in tarred, compressed format - data folder: datasets in tarred and compressed format - doc folder: detailed QC-document (OLYMPEX_sonde_qc.pdf), readme files for each data level, and sample fortran programs to read ASCII datasets Send questions to: paulc@atmos.colostate.edu

NPOL radar rainmap Sounding time-series cross-section from 16 Nov. 11Z to 18 Nov. 11Z for atmospheric river event; frontal passage late on 17 Nov. GPM overpass Steve, you will have to check with Brenda regarding time of GPM overpass. Additional sounding cross-sections based on KUIL and NPOL soundings can be found at: http://johnson.atmos.colostate.edu/public/paulc/OLYMPEX/

KUIL at 17 Nov. 11Z KUIL at 17 Nov. 23Z Skew-T plots highlighting frontal passage late on 17 November. Note: loss of signal at times at upper-levels at NPOL site. UHF antenna was changed on 19 Nov. which fixed this problem. NPOL at 17 Nov. 11z NPOL at 17 Nov. 23Z NPOL at 18 Nov. 02Z Note: wind barbs (knots) plotted at 50 hPa resolution

KUIL at 17 Nov. 11Z KUIL at 17 Nov. 23Z Skew-T plots highlighting frontal passage late on 17 November. Note: loss of signal at times at upper-levels at NPOL site. UHF antenna was changed on 19 Nov. which fixed this problem. NPOL at 17 Nov. 11z NPOL at 17 Nov. 23Z NPOL at 18 Nov. 02Z Note: wind barbs (knots) plotted at 10 hPa resolution