Download
1 / 25

Intercomparisons of Water Vapor Measurements during IHOP_2002 – Radiosonde and Dropsonde - PowerPoint PPT Presentation


  • 119 Views
  • Uploaded on

Intercomparisons of Water Vapor Measurements during IHOP_2002 – Radiosonde and Dropsonde. Junhong (June) Wang NCAR Atmospheric Technology Division. Acknowledgement: Kate Beierle, Scot Loeher, ARM EDC. Outline:. Goals for intercomparisons

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Intercomparisons of Water Vapor Measurements during IHOP_2002 – Radiosonde and Dropsonde' - tahlia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Intercomparisons of Water Vapor Measurements during IHOP_2002 – Radiosonde and Dropsonde

Junhong (June) Wang

NCAR Atmospheric Technology Division

Acknowledgement: Kate Beierle, Scot Loeher, ARM EDC


Outline: IHOP_2002

  • Goals for intercomparisons

  • Summary of Comparisons between Snow White and Vaisala RS80-H/VIZ-B2 during IHOP_2002

  • Comparison of Radiosonde Data at Norman, OK and ARM-B6 site (Purcell, OK) from 1996-2002

  • Comparison of dropsonde and radiosonde data during IHOP_2002


Errors in Observation system: IHOP_2002

  • Natural Error:

  • Instrument error (systematic and radom)

  • Error of representativeness

  • Gross Error:

  • Improperly calibrated instruments

  • Incorrect registration of observations

  • Incorrect coding of observations

  • Telecommunication errors

  • Goals:

  • Mean errors/biases for the climate community

  • Observation error variances (only instrument error) for the data assimilation community


Summary IHOP_2002

  • ±5%:

  • Typical accuracy

  • Requirements for synoptic meteorology

Wang et al. (2003 )

http://www.atd.ucar.edu/homes/junhong/paper/Refsonde-GRL.pdf


Comparisons of radiosonde data at Norman, OK and ARM-B6 site (Purcell, OK) from 1996 to 2002

  • Two sites are ~16 miles (25 km) apart.

  • VIZ-B, VIZ-B2, Vaisala RS80-H, Vaisala RS90 were used at two sites during 1996-2002.

  • 490 pairs of soundings launched within half hour and sampling the same air mass are found for comparisons.


VIZ-B/RS80-H B2/RS80H RS80-H/RS80-H RS80-H/RS90

(97) (131) (158) (104)


RH RS80-H/RS90


Monthly Mean RH Profiles RS80-H/RS90

Norman

ARM-B6


T RS80-H/RS90



Estimation of Instrument Error Variances RS80-H/RS90

Richner and Philips (1982)

“The Radiosonde Intercomparison SONDEX”



% MR difference between LASE and dropsonde RS80-H/RS90

CAMEX-3

~8%

RD93-TWC

CAMEX-4

RD93-RS90

From Vance et al. (2002)

From Kooi et al. (2002)

RH dry bias from pervious studies


Homestead (RS80-H 7) RS80-H/RS90

ARM-CF (RS90 2)

Comparisons of dropsonde and radiosonde data: RH



Performance in Clouds (Dycoms-II) RS80-H/RS90

Marine Stratus Cumulus clouds


Time lag error RS80-H/RS90

Time-lag Error


Conclusions RS80-H/RS90

  • The Sippican (VIZ) carbon hygristor used in 14% of global radiosonde stations fails to respond to humidity changes in the UT, sometimes even in the middle troposphere. This lack of response has produced significant and artificial humidity changes in the UT when the transition occurred and resulted in incapability of carbon hygristor to measure vertical and seasonal variations of humidity in UT.

  • Vaisala RS80-H Humicap used in ~51% of global radiosonde stations agrees very well with the SW in the middle and lower troposphere, but has dry biases in the UT.

  • Comparisons of seven years of data from two neighboring stations (Norman and ARM-B6) show unexplained significant and consistent drier RS90 than RS80-H (~5%) in UT and warmer temperature (~0.5C) in the middle and upper troposphere at ARM-B6 than at Norman when Vaisala sondes were launched at both sites.

  • The dry bias in dropsonde humidity data found by previous studies are preliminarily evaluated by comparing with co-located radiosonde data during IHOP. The comparison shows good agreements except inside moist layers.


Comparisons between VIZ and RS80-H RS80-H/RS90

No response


Descending region RS80-H/RS90

Ascending region

Descending

region

Matching dropsonde with C-130 ascending/descending profile



RS90 (B6) v.s. RS80H (Norman) RS80-H/RS90

during IHOP (N=52)

Comparisons between RS80-H and RS80-H/RS90

RS80H (B6) v.s. RS80H (Norman)

1999/2000 (N=158)


Significant and consistent drier RS90 than RS80-H in UT RS80-H/RS90

Significant and consistent warmer temperature in the middle and upper troposphere at ARM-B6 than at Norman when Vaisala sondes were launched at both sites.


Homestead (RS80-H 7) RS80-H/RS90

ARM-CF (RS90 2)

Comparisons of dropsonde and radiosonde data: RH


ad