IHOP Radiosonde and Dropsonde Data: Highlights and Problems

Junhong (June) Wang Junhong (June) Wang Kate BeierleKate BeierleNCAR/ATDNCAR/ATD

1. Radiosonde data• Summary• Humidity sensors• Problems

2. Dropsonde data• Summary• Scientific Highlights• Problems

Summary of all radiosonde data from IHOPSummary of all radiosonde data from IHOP

Radiosonde Systems

Number of soundings

Radiosonde Types

Sites Time (UTC)

NWS 1653 (410)Vaisala RS80-H

& VIZ14

00 and 12 UTC every day, 11 IOPs at 15, 18 21 UTC, and 4 IOPS at 18, 21, 03 UTC

ARM 862 Vaisala RS905 (C1, B1, B4,

B5, B6)02, 05, 08, 11, 14, 17, 20, 23 UTC

ISS 138 Vaisala RS80-H Homestead18 UTC every day, and various times for IOPs

Ref. Sonde 16 Ref/RS80H/VIZ Homestead 18 UTC and others

Mobile_CLASS 60 RS80-H mobile various

Mobile_GLASS1 74 RS80-H mobile various

Mobile_GLASS2 77 RS80-H mobile various

Total 2625 3 types  19 + 3 mobile   Various

Reference sonde

400MHz transmitter

GPS receiver

Swiss Radiosonde C34•SW chilled-mirror DP hygrometer – reference humidity sensor•Carbon hygristor•Copper-constantan thermocouple•Hypsometer

Vaisala RS80

NWS VIZ B-2

Reference radiosonde

Radiosondes

RS90 (~1993): Smaller THERMOCAPHeated twin F-HUMICAP

VIZ-B2: Rod thermistorCarbon hygristor

Vaisala RS80-H

VIZ B-2

RS80-H (~1990): THERMOCAPF-HUMICAP

SnowWhite Chilled-mirror dewpoint hygrometer SnowWhite Chilled-mirror dewpoint hygrometer

•Fast response

• No influences of radiation, wind and others

• Accurate measurement of dew/frost point

• Detects clouds and measures their liquid/solid water

• Needs no individual calibration and recalibration after recovered

ThermocoupleMirror

Peltier

Scattering light detectorReflecting light detector

Heated sensor housing

Data quality control for Data quality control for ATD Radiosonde DataATD Radiosonde Data

2. ASPEN

3. Individual 3. Individual Skew-T examinationSkew-T examination

4. Comparisons of 4. Comparisons of prelaunch and surface dataprelaunch and surface data

5. 5. Comparisons with other data

1. In-field data processing

Aspirator upgrade for ISSAspirator upgrade for ISS

Old

New

Summary of all dropsonde data from IHOPSummary of all dropsonde data from IHOP

Missions Falcon Lear Total

BLH 19 17 36

M LLJ 62 93 155

CI 7 169 176

E LLJ 0 53 53

Total 88 332 420

1. PTU/W profiles

2. Validation for newer WV instruments

NCAR GPS DropsondeNCAR GPS Dropsonde

Large parachute Small parachute

MLLJ on June 9 (1200-1930 UTC)MLLJ on June 9 (1200-1930 UTC)

1. Box flight path (clockwise)

2. Clear sky in the domain

3. LLJ on the northern leg

4. Lear: 48 (took off from NW corner, ~50 km, two box flights)

5. Falcon: 21 (took off from SE corner, ~50 km)

6. Mapping moisture and intercomparison with DIAL, LASE, NAST

T/RH variations for two Lear box flights June 9T/RH variations for two Lear box flights June 9

RF9 RF10

MLLJ (East-West on the Northern Leg on June 9)MLLJ (East-West on the Northern Leg on June 9)

Specific Humidity (g/kg)DIAL on Falcon

Inversion-capped moist layer

Two-layer moisture

CI on June 12 CI on June 12 (1900-2200 UTC)(1900-2200 UTC)

Dry Line

Performance in Performance in Clouds Clouds

CI May 22CI May 2222:14-22:39 UT22:14-22:39 UT

1. ASPEN(limit, buddy, outlier, filter, etc.)

2. Individual Skew-T examination2. Individual Skew-T examination

3. Histograms of PTU and wind3. Histograms of PTU and wind

4. Time series of PTU and wind4. Time series of PTU and wind

5. Comparisons with other data

Data quality control for ATD Dropsonde DataData quality control for ATD Dropsonde Data

Geopotential height problems and solutionsGeopotential height problems and solutions

Before

After

2. Corrections:

Good soundings

Integrate from surface up

Surface elevation

Soundings with missing data above surface

Integrate from FL down

Add PTU to FL

Corrected heights

Integrate from flight-level down

Unknown surface altitude

1. No flight-level PTU data2. Use flight-level height but 1st available pressure (~20s)

~200-300 m overestimate of heights

1. Problems:

Geo-potential height data after correctionsGeo-potential height data after corrections

Missing data before landing

Importance Notes Importance Notes for IHOP radiosonde/dropsonde datafor IHOP radiosonde/dropsonde data

• Do not use reference sonde pressure and wind data:

1. The reference sonde (RS) uses a hypsometer to measure pressure. Unfortunately the hypsometer was not stable and has all kinds of problems.

2. We didn't correct balloon swing at all for winds and had quite big balloon swing because of bigger balloons used.

• Sensor arm heating error in radiosonde data at Homestead:

1. The SAH error depends on a lot of factors

2. Different impacts for T and RH: 40-60 s (200-300m) for RH, negligible for T.

• Take precautious about dropsonde geopotential data:

The Geopotential height problems in IHOP dropsonde data are investigated and corrected. But there may be some un-identified problems in some individual soudnings.

Errors/Biases and Error variances in radiosonde and dropsonde data will show latter