the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Ground- and ship-based microwave radiometer measurements during EUREC4A
Andreas Foth
Heike Kalesse-Los
Mario Mech
Claudia Acquistapace
Friedhelm Jansen
Ulrich Löhnert
Bernhard Pospichal
Johannes Röttenbacher
Susanne Crewell
Bjorn Stevens
Abstract. During the EUREC4A field study, microwave radiometric measurements were performed at Barbados Cloud Observatory (BCO) and aboard the RV Meteor and RV Maria S Merian. We present retrieved Integrated Water Vapor (IWV), Liquid Water Path (LWP) and temperature and humidity profiles as a unified, quality-controlled, multi-site dataset on a three second temporal resolution for a core period between January 19, 2020 and February 14, 2020 in which all instruments were operational. 14-channel K- and V-band measurements were performed at BCO and aboard the RV Meteor, and combined radar-radiometer measurements of a W-band Doppler radar with a single-channel radiometer instrument were conducted at 89 GHz onboard the RV Meteor and RV Maria S Merian. Mean IWV of 31.8 kgm−2 matches independent radiosoundings at BCO with a rootmean-square difference of 1.1 kgm−2. Mean LWP conditions in confident cloudy, non-precipitating conditions ranged between 66.5 gm−2 at BCO to 40.4 gm−2 aboard the RV Maria S Merian. Aboard the ships, 90 % of LWP was below 120 gm−2 with an uncertainty of 30 % at LWP of 50 gm−2. Up to 30 % of confident cloudy profiles ranged below the LWP detection limit due to optically thin clouds.
The data set comprises of processed raw-data (Level 1), full quality-controlled post-processed instrument data (Level 2), a unified temporal resolution (Level 3), and a ready-to-use multi-site time series of IWV and LWP (Level 4), available to the public via AERIS (https://doi.org/10.25326/454, Schnitt et al., 2023). The data set complements the airborne LWP measurements conducted during EUREC4A and provides a benchmark tool for model-observation studies.
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Sabrina Schnitt et al.
Status: final response (author comments only)
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RC1: 'Comment on essd-2023-140', Anonymous Referee #1, 14 May 2023
This paper provides an overview of the IWV, LWP, and thermodynamic profiles retrieved from two ground-based multi-channel microwave radiometers and the passive observations from two single-frequency cloud radars. Details are provided on the retrieval methods. A detailed analysis and comparison of the IWV and LWP, including a discussion of the sensitivity of the different systems and potential sources of bias, was included. Overall, I find this paper to be well-constructed, the writing clear and precise, and that the paper should be accepted after some relatively minor suggestions are addressed. Nice job, authors!
- Line 193: Would you please provide motivation to why you selected these thresholds to use in your clipping?
- L193: And presumably, “clipping” means that data above these thresholds are considered “bad” and not used in future analyses (or included in the dataset you’ve archived)?
- L293: I believe you mean it is clear if there is no observed backscatter above some threshold; please indicate that threshold. Also, what is the model of the ceilometer used in this study, and is the same model used on all three locations (BCO as well as the two RVs)?
- L295: I believe you again mean “flagged clear if the cloud radar does not indicate any reflectivity above X dBZ between 500m…”
- L301: for confidently cloudy, do you require both the radar and ceilometer see the cloud at (approximately) the same height?
- General question: how do you identify cases where the radar sees an ice cloud, and prevent these occurrences from affecting your statistics?
- L347: it would be good to reference a paper here that shows that the visible, infrared, and microwave measurements have different sensitivities to liquid clouds. One possible example from the ARM program is Turner et al. BAMS 2007.
- L362: the single-channel retrievals have two aspects that result in the lower LWP noise values: (a) the IWV is fixed, and (b) the observation frequency is in the W-band, where the strength of the WV absorption is stronger. You mention the latter at L381, but it could be mentioned here too.
- L383, and also at L362: if you included realistic uncertainties in the IWV used in the single channel LWP retrieval from the radars, it would result in larger uncertainties in the retrieved LWP. But how much larger? Would you please quantify that?
- L429: you need to include a reference to the 2 degrees of freedom for MWR temperature retrievals. There are several papers by coauthor Löhnert that could be referenced here.
- L437: Would using a physical-iterative retrieval result in improved statistics, relative to your statistical retrieval, at this site? It might be interesting to include a sentence about that (either here or in the discussion)
Again, very nice paper.
Citation: https://doi.org/10.5194/essd-2023-140-RC1 -
RC2: 'Comment on essd-2023-140', Anonymous Referee #2, 30 May 2023
The comment was uploaded in the form of a supplement: https://essd.copernicus.org/preprints/essd-2023-140/essd-2023-140-RC2-supplement.pdf
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AC1: 'Comment on essd-2023-140', Sabrina Schnitt, 25 Jul 2023
The comment was uploaded in the form of a supplement: https://essd.copernicus.org/preprints/essd-2023-140/essd-2023-140-AC1-supplement.pdf
Sabrina Schnitt et al.
Data sets
Ground- and ship-based microwave radiometer measurements during EUREC4A Sabrina Schnitt, Andreas Foth, Heike Kalesse-Los, Mario Mech, and Claudia Acquistapace https://doi.org/10.25326/454
Sabrina Schnitt et al.
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