Universität zu Köln

Bock, Olivier ORCID: 0000-0001-5980-938X, Bosser, Pierre ORCID: 0000-0001-5439-9860, Flamant, Cyrille ORCID: 0000-0002-8309-6495, Doerflinger, Erik, Jansen, Friedhelm, Fages, Romain, Bony, Sandrine and Schnitt, Sabrina ORCID: 0000-0002-3949-770X (2021). Integrated water vapour observations in the Caribbean arc from a network of ground-based GNSS receivers during EUREC(4)A. Earth Syst. Sci. Data, 13 (5). S. 2407 - 2437. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1866-3516

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Abstract

Ground-based Global Navigation Satellite System (GNSS) measurements from nearly 50 stations distributed over the Caribbean arc have been analysed for the period 1 January-29 February 2020 in the framework of the EUREC(4)A (Elucidate the Couplings Between Clouds, Convection and Circulation) field campaign. The aim of this effort is to deliver high-quality integrated water vapour (IWV) estimates to investigate the moisture environment of mesoscale cloud patterns in the trade winds and their feedback on the large-scale circulation and energy budget. This paper describes the GNSS data processing procedures and assesses the quality of the GNSS IWV retrievals from four operational streams and one reprocessed research stream which is the main data set used for offline scientific applications. The uncertainties associated with each of the data sets, including the zenith tropospheric delay (ZTD)-to-IWV conversion methods and auxiliary data, are quantified and discussed. The IWV estimates from the reprocessed data set are compared to the Vaisala RS41 radiosonde measurements operated from the Barbados Cloud Observatory (BCO) and to the measurements from the operational radiosonde station at Grantley Adams International Airport (GAIA), Bridgetown, Barbados. A significant dry bias is found in the GAIA humidity observations with respect to the BCO sondes 2:9 kgm(-2)) and the GNSS results (1:2 kgm(-2)). A systematic bias between the BCO sondes and GNSS is also observed (1.7 kgm(-2)), where the Vaisala RS41 measurements are moister than the GNSS retrievals. The IWV estimates from a collocated microwave radiometer agree with the BCO soundings after an instrumental update on 27 January, while they exhibit a dry bias compared to the soundings and to GNSS before that date. IWV estimates from the ECMWF fifth-generation reanalysis (ERA5) are overall close to the GAIA observations, probably due to the assimilation of these observations in the reanalysis. However, during several events where strong peaks in IWV occurred, ERA5 is shown to significantly underestimate the GNSS-derived IWV peaks. Two successive peaks are observed on 22 January and 23-24 January which were associated with heavy rain and deep moist layers extending from the surface up to altitudes of 3.5 and 5 km, respectively. ERA5 significantly underestimates the moisture content in the upper part of these layers. The origins of the various moisture biases are currently being investigated.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Bock, Olivier UNSPECIFIED orcid.org/0000-0001-5980-938X UNSPECIFIED Bosser, Pierre UNSPECIFIED orcid.org/0000-0001-5439-9860 UNSPECIFIED Flamant, Cyrille UNSPECIFIED orcid.org/0000-0002-8309-6495 UNSPECIFIED Doerflinger, Erik UNSPECIFIED UNSPECIFIED UNSPECIFIED Jansen, Friedhelm UNSPECIFIED UNSPECIFIED UNSPECIFIED Fages, Romain UNSPECIFIED UNSPECIFIED UNSPECIFIED Bony, Sandrine UNSPECIFIED UNSPECIFIED UNSPECIFIED Schnitt, Sabrina UNSPECIFIED orcid.org/0000-0002-3949-770X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-599602
DOI:	10.5194/essd-13-2407-2021
Journal or Publication Title:	Earth Syst. Sci. Data
Volume:	13
Number:	5
Page Range:	S. 2407 - 2437
Date:	2021
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1866-3516
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language REFRACTIVE-INDEX; GPS METEOROLOGY; MODEL; ERRORS; TEMPERATURE; PRESSURE; IMPACT; DELAY; AIR Multiple languages Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59960