The Virga-Sniffer – a new tool to identify precipitation evaporation using ground-based remote-sensing observations

Kalesse, Heike; Kötsche, Anton; Foth, Andreas; Röttenbacher, Johannes; Vogl, Teresa; Witthuhn, Jonas

doi:10.5194/amt-16-1683-2023

Cited by 4 publications

(12 citation statements)

References 34 publications

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“…To ensure that the Virga-Sniffer for the BCO is configured optimally, we establish a statistical comparison of the results of the Virga-Sniffer at the BCO, with the results of Kalesse-Los et al ( 2023) during the EUREC 4 A campaign. Please again note the following differences between the study by Kalesse-Los et al (2023) and this present study:…”

Section: Virga-sniffer Results Including Haze Echoesmentioning

confidence: 71%

“…The Virga-Sniffer is a Python package tool developed by Kalesse-Los et al (2023) This ensures that tilted fall streaks and vertically separated cloud layers are captured. Radar-based surface rain flag is set if Z e is larger than 0 dBZ in the first radar rage gate.…”

Section: Virga-sniffer Toolmentioning

confidence: 99%

“…More recently, Kalesse-Los et al (2023) introduced the functionality of a tool, called the Virga-Sniffer, to distinguish precipitation that fully evaporates in dry subcloud layers (virga) from precipitation that reaches the ground based on a synergy of cloud radar and ceilometer measurements. During the Elucidating the Role of Cloud-Circulation Coupling in Climate (EUREC 4 A) field experiment (Stevens et al, 2021) in January and February 2020 in the tropical western Atlantic, they observed that a substantial amount of trade wind cumuli over the research vessel (RV) Meteor produce virga (Kalesse-Los et al, 2023).…”

mentioning

confidence: 99%

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Discriminating between "Drizzle or rain" and sea salt aerosols in Cloudnet for measurements over the Barbados Cloud Observatory

Roschke,

Witthuhn,

Klingebiel

et al. 2024

Preprint

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Abstract. The highly sensitive Ka-band cloud radar at the Barbados Cloud Observatory (BCO) frequently reveals radar reflectivities below -50 dBZ within updrafts and below the cloud base of cumulus clouds. These so-called haze echoes are signals from hygroscopically grown sea salt aerosols. Within the Cloudnet target classification scheme, haze echoes are generally misclassified as precipitation ("Drizzle or rain"). We present a technique to discriminate between "Drizzle or rain" and sea salt aerosols in Cloudnet that is applicable to marine Cloudnet sites. The method is based on deriving heuristic probability functions utilizing a combination of cloud radar reflectivity factor, radar mean Doppler velocity and ceilometer attenuated backscatter coefficient. The method is crucial for investigating the occurrence of precipitation and significantly improves the Cloudnet target classification scheme for the measurements over the BCO. The results are validated against the amount of precipitation detected by the Virga-Sniffer tool. We analyze data for the measurements in the vicinity of the BCO covering two years (July 2021–July 2023) as well as during the ElUcidating the RolE of Cloud–Circulation Coupling in ClimAte (EUREC4A) field experiment that took place in Jan–Feb 2020. A first-ever statistical analysis of the Cloudnet target classification product including the new "haze echo" target over two years at the BCO is presented. In the atmospheric column above the BCO, “Drizzle or rain" is on average more frequent during the dry season compared to the wet season, due to the higher occurrence of warm clouds contributing to the amount of precipitation. Haze echoes are identified about four times more often during the dry season compared to the wet season. The frequency of occurrence of "Drizzle or rain" in Cloudnet caused by misclassified haze echoes is overestimated by up to 16 %. Supported by the Cloudnet statistics and the results obtained from the Virga-Sniffer tool, 48 % of detected warm clouds in the dry and wet season precipitate. The proportion of precipitation evaporating fully before reaching the ground (virga) is higher during the dry season. During EUREC4A, precipitation from warm clouds was found to reach the ground more frequently over the RV Meteor compared to the BCO.

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Section: Virga-sniffer Results Including Haze Echoesmentioning

confidence: 71%

Section: Virga-sniffer Toolmentioning

confidence: 99%

mentioning

confidence: 99%

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Discriminating between "Drizzle or rain" and sea salt aerosols in Cloudnet for measurements over the Barbados Cloud Observatory

Roschke,

Witthuhn,

Klingebiel

et al. 2024

Preprint

View full text Add to dashboard Cite

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“…During EUREC 4 A, BCOHAT measurements were complemented by HATPRO measurements aboard the Meteor performed by the Leipzig Institute for Meteorology (LIM), here referred to as LIMHAT. Aboard the Meteor, a 94 GHz cloud radar (Küchler et al, 2017) was installed, equipped with a passive radiometer channel measuring T B at 89 GHz (Kalesse-Los et al, 2023), here referred to as LIMRAD. A similar instrument was stationed aboard the Merian (Acquistapace et al, 2022), here referred to as MSMRAD.…”

Section: Introductionmentioning

confidence: 99%

“…LIMRAD was operated with two different chirp programs specified inKalesse-Los et al (2023). Between January 17 and 29, 2020, and Jan 31 and February 28, 2020, the temporal resolution of LIMRAD was 2.9 s and 1.6 s, respectively.…”

mentioning

confidence: 99%

Ground- and ship-based microwave radiometer measurements during EUREC4A

Schnitt

Foth

Kalesse

et al. 2023

Preprint

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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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Derivation of aerial insect concentration with a 94 GHz FMCW cloud radar

Lochmann,

Kalesse-Los,

Haest

et al. 2024

Preprint

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Aerial insects are vital for nature and society. Though methods to observe flying insects have consistently improved in the last decades, insects remain difficult to monitor systematically and consistently over large spatial and temporal scales. Remote sensing with radars has proved to be one of the more effective tools for observation. However, as radars are most sensitive to targets similar in size to the radar wavelength, the detectable sub-group of aerial insects of a certain size range depends on the employed radar. Here, we present a novel method based on data of a zenith-pointing W-band (94 GHz, lambda = 0.32 cm) Doppler cloud radar to estimate insect concentration in a vertical profile. Multiple meteorological state-of-the-art algorithms are combined to extract insect signals from the radar data and quantify their abundance from 50m to 1000m above the ground. For evaluation, this method is applied to Doppler cloud radar data from a summertime 30 day observation period in central Germany. Results are compared to data from an X-band (9.4 GHz, lambda = 3.2 cm) radar in the same region. Aerial insect concentration derived from the W-band radar, which is sensitive to insects in the mm size range, is substantially higher than from the X-band radar, detecting insects in the cm size range. In addition, diel flight timings vary between the different sub-groups of aerial insects observed by the two radar instruments. With its superior sensitivity to smaller insects like aphids, the proposed methodology complements existing entomological radar techniques and contributes to achieving a more complete description of aerial insect activity.

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The Virga-Sniffer – a new tool to identify precipitation evaporation using ground-based remote-sensing observations

Cited by 4 publications

References 34 publications

Discriminating between "Drizzle or rain" and sea salt aerosols in Cloudnet for measurements over the Barbados Cloud Observatory

Discriminating between "Drizzle or rain" and sea salt aerosols in Cloudnet for measurements over the Barbados Cloud Observatory

Ground- and ship-based microwave radiometer measurements during EUREC4A

Derivation of aerial insect concentration with a 94 GHz FMCW cloud radar

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