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Title: Precipitable Water Vapor Characterization In The Gulf Of Cadiz Region (Southwestern Spain) Based On Sun Photometer, GPS And Radiosonde Data

Abstract

Column integrated water vapor (IWV) data in the Gulf of Cádiz area (Southwestern Spain) are analyzed during the period 2001 to 2005 with two aims: 1) to establish the climatology over this area using three different techniques, such as Sun-Photometer (SP), Global Position System (GPS) and Radiosondes, and 2) to take advantage of this comparative process to assess the quality of radiometric IWV data collected at the RIMA-AERONET station. The 5 years of climatological series gives a mean value of about 2 cm (STD=0.72) and a clear seasonal behavior as a general feature, with the highest values in summer and the lowest in winter. In the multi-annual monthly means basis, the highest values are reached in August-September, with a mean value of 2.5-2.6 cm, whereas the lowest are obtained in January-February, with an average of 1.4-24 1.5. However the most relevant results for this area is the observed local minimum in July, occurring during the maximum of desert dust intrusions in the southern Iberian Peninsula. A comparison process allows us to evaluate the agreement of IWV data sets between these three different techniques at different temporal scales because of different time sampling. On a daily basis and taking GPS asmore » the reference value we have a bias or difference between Radiosonde and GPS measurements for the entire data base of 0.07 cm (relative bias of 3%) and RMSE of 0.33. For SP-GPS we have a bias of 0.14 cm (about 7%) and RMSE of 0.37. On a monthly basis the differences between Radiosonde and GPS values varies from summer with 2% to winter with -8% and between SP and GPS values from 3% in summer to -14% in winter. The observed bias between GPS and SP varies during each SP operational period, with lower values at the beginning of the measurements and increasing until the end of its measurement term and with the bias values being quite dependent on each individual SP. The observed differences highlight the importance of drift in each Sun-Photometer, because of filter aging or other calibration problems. Hence the comparison with GPS appears to be a powerful tool to assess the quality of Sun-Photometer for IWV retrieval.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
990546
Report Number(s):
PNNL-SA-64919
KP1701000; TRN: US201020%%406
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research. D. (Atmospheres), 115:Article No. D18103
Additional Journal Information:
Journal Volume: 115
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; AGING; CALIBRATION; DESERTS; DUSTS; GLOBAL POSITIONING SYSTEM; SAMPLING; SPAIN; SUN; WATER VAPOR; precipitable water vapor; Sun-Photometer; Global Position System (GPS); Radiosonde; comparison; RIMA-AERONET

Citation Formats

Torres, B, Cachorro, V E, Toledano, C, Ortiz de Galisteo, J P, Berjon, A, de Frutos, A M, Bennouna, Yasmine, and Laulainen, Nels S. Precipitable Water Vapor Characterization In The Gulf Of Cadiz Region (Southwestern Spain) Based On Sun Photometer, GPS And Radiosonde Data. United States: N. p., 2010. Web. doi:10.1029/2009JD012724.
Torres, B, Cachorro, V E, Toledano, C, Ortiz de Galisteo, J P, Berjon, A, de Frutos, A M, Bennouna, Yasmine, & Laulainen, Nels S. Precipitable Water Vapor Characterization In The Gulf Of Cadiz Region (Southwestern Spain) Based On Sun Photometer, GPS And Radiosonde Data. United States. https://doi.org/10.1029/2009JD012724
Torres, B, Cachorro, V E, Toledano, C, Ortiz de Galisteo, J P, Berjon, A, de Frutos, A M, Bennouna, Yasmine, and Laulainen, Nels S. 2010. "Precipitable Water Vapor Characterization In The Gulf Of Cadiz Region (Southwestern Spain) Based On Sun Photometer, GPS And Radiosonde Data". United States. https://doi.org/10.1029/2009JD012724.
@article{osti_990546,
title = {Precipitable Water Vapor Characterization In The Gulf Of Cadiz Region (Southwestern Spain) Based On Sun Photometer, GPS And Radiosonde Data},
author = {Torres, B and Cachorro, V E and Toledano, C and Ortiz de Galisteo, J P and Berjon, A and de Frutos, A M and Bennouna, Yasmine and Laulainen, Nels S},
abstractNote = {Column integrated water vapor (IWV) data in the Gulf of Cádiz area (Southwestern Spain) are analyzed during the period 2001 to 2005 with two aims: 1) to establish the climatology over this area using three different techniques, such as Sun-Photometer (SP), Global Position System (GPS) and Radiosondes, and 2) to take advantage of this comparative process to assess the quality of radiometric IWV data collected at the RIMA-AERONET station. The 5 years of climatological series gives a mean value of about 2 cm (STD=0.72) and a clear seasonal behavior as a general feature, with the highest values in summer and the lowest in winter. In the multi-annual monthly means basis, the highest values are reached in August-September, with a mean value of 2.5-2.6 cm, whereas the lowest are obtained in January-February, with an average of 1.4-24 1.5. However the most relevant results for this area is the observed local minimum in July, occurring during the maximum of desert dust intrusions in the southern Iberian Peninsula. A comparison process allows us to evaluate the agreement of IWV data sets between these three different techniques at different temporal scales because of different time sampling. On a daily basis and taking GPS as the reference value we have a bias or difference between Radiosonde and GPS measurements for the entire data base of 0.07 cm (relative bias of 3%) and RMSE of 0.33. For SP-GPS we have a bias of 0.14 cm (about 7%) and RMSE of 0.37. On a monthly basis the differences between Radiosonde and GPS values varies from summer with 2% to winter with -8% and between SP and GPS values from 3% in summer to -14% in winter. The observed bias between GPS and SP varies during each SP operational period, with lower values at the beginning of the measurements and increasing until the end of its measurement term and with the bias values being quite dependent on each individual SP. The observed differences highlight the importance of drift in each Sun-Photometer, because of filter aging or other calibration problems. Hence the comparison with GPS appears to be a powerful tool to assess the quality of Sun-Photometer for IWV retrieval.},
doi = {10.1029/2009JD012724},
url = {https://www.osti.gov/biblio/990546}, journal = {Journal of Geophysical Research. D. (Atmospheres), 115:Article No. D18103},
number = ,
volume = 115,
place = {United States},
year = {Thu Sep 16 00:00:00 EDT 2010},
month = {Thu Sep 16 00:00:00 EDT 2010}
}