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Title: A comparison of water vapor quantities from model short-range forecasts and ARM observations

Abstract

Model evolution and improvement is complicated by the lack of high quality observational data. To address a major limitation of these measurements the Atmospheric Radiation Measurement (ARM) program was formed. For the second quarter ARM metric we will make use of new water vapor data that has become available, and called the 'Merged-sounding' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Darwin Australia (DAR) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both DAR and NSA. The merged-sounding data have been interpolated to 37 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3 hourly data for direct comparison to our model output.

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
928538
Report Number(s):
UCRL-TR-219973
TRN: US200812%%505
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; METRICS; RADIATIONS; WATER VAPOR

Citation Formats

Hnilo, J J. A comparison of water vapor quantities from model short-range forecasts and ARM observations. United States: N. p., 2006. Web. doi:10.2172/928538.
Hnilo, J J. A comparison of water vapor quantities from model short-range forecasts and ARM observations. United States. doi:10.2172/928538.
Hnilo, J J. Fri . "A comparison of water vapor quantities from model short-range forecasts and ARM observations". United States. doi:10.2172/928538. https://www.osti.gov/servlets/purl/928538.
@article{osti_928538,
title = {A comparison of water vapor quantities from model short-range forecasts and ARM observations},
author = {Hnilo, J J},
abstractNote = {Model evolution and improvement is complicated by the lack of high quality observational data. To address a major limitation of these measurements the Atmospheric Radiation Measurement (ARM) program was formed. For the second quarter ARM metric we will make use of new water vapor data that has become available, and called the 'Merged-sounding' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Darwin Australia (DAR) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both DAR and NSA. The merged-sounding data have been interpolated to 37 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3 hourly data for direct comparison to our model output.},
doi = {10.2172/928538},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 17 00:00:00 EST 2006},
month = {Fri Mar 17 00:00:00 EST 2006}
}

Technical Report:

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  • Model evolution and improvement is complicated by the lack of high quality observational data. To address a major limitation of these measurements the Atmospheric Radiation Measurement (ARM) program was formed. For the second quarter ARM metric we will make use of new water vapor data that has become available, and called the “Mergedsounding” value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Darwin Australia (DAR) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGPmore » and October 2004 for both DAR and NSA. The merged-sounding data have been interpolated to 37 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3 hourly data for direct comparison to our model output.« less
  • For the fourth quarter ARM metric we will make use of new liquid water data that has become available, and called the “Microbase” value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Tropical West Pacific (TWP) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both TWP and NSA. The Microbase data have been averaged to 35 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averagedmore » to 3hourly data for direct comparison to our model output.« less
  • For the fourth quarter ARM metric we will make use of new liquid water data that has become available, and called the 'Microbase' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Tropical West Pacific (TWP) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both TWP and NSA. The Microbase data have been averaged to 35 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averagedmore » to 3hourly data for direct comparison to our model output.« less
  • These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquidmore » water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation.« less
  • Studies of radiosonde accuracy have tended to involve intercomparisons among different radiosonde types. One goal of these intercomparisons has been to quantify biases or other systematic errors related to the kinds of sensors employed. Little apparent attention has been paid, however, to the operational uncertainty associated with a single sensor type. The US Department of Energy`s Atmospheric Radiation Measurement (ARM) Program has used a single radiosonde type since beginning field operations in 1992 at its Cloud and Radiation Testbed (CART) site. Because of the dependence of ARM Science Team experiments on measurements of the atmospheric state, considerable interest exists withinmore » the program in quantifying the uncertainty associated with radiosonde measurements. The September 1996 Water Vapor Intensive Operations Period (WVIOP) provided an excellent opportunity to investigate further the operational performance of the radiosondes used by ARM.« less