scholarly journals Observations of Quasi-Stationary and Shallow Orographic Snow Clouds: Spatial Distributions of Supercooled Liquid Water and Snow Particles

2005 ◽  
Vol 133 (4) ◽  
pp. 743-751 ◽  
Author(s):  
Kenichi Kusunoki ◽  
Masataka Murakami ◽  
Narihiro Orikasa ◽  
Mizuho Hoshimoto ◽  
Yoshinobu Tanaka ◽  
...  
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Indirect Evidence ◽  
Supercooled Liquid ◽  
Small Scale ◽  
Mountain Range ◽  
Spatial Distributions ◽  
Liquid Water Path ◽  
Cyclonic Storm ◽  
Water Path

On 25 February 1999, due to a winter monsoon after a cyclonic storm, orographic snow clouds formed under conditions of weak cold advection on the western side of the central mountain range of Japan. In this study, the Ka-band Doppler radar and vehicle-mounted microwave radiometer and 2D-Grey imaging probe were used to obtain unique datasets for analyzing the spatial distributions of microphysical structures of the snow clouds at the windward slope. The liquid water path, number concentration of snow particles (0.1–6.4 mm diameter), and precipitation rate were found to be correlated with altitude. The greater concentration of larger particles tended to appear up the slope. The echo top was at about 2.5 km (−30 dBZ), and the relatively strong echo region (>−3 dBZ) appeared at 5 km up the slope and extended nearly parallel to the slope. According to the echo pattern, the ice water path increased with terrain height and reached the maximum intensity at about 14 km up the slope. These observations provide indirect evidence that terrain-induced updrafts lead to the generation and growth of supercooled cloud droplets and indicate that the riming process plays an important role in the growth of snow particles at higher altitudes. In this paper, it is confirmed that the abundance of supercooled liquid water (SLW) during intensified monsoon flow is due to larger water production rates caused by higher vertical velocities induced by topography. Furthermore, it can be shown that small-scale terrains enhance localized updrafts embedded within the larger-scale flow and have noticeable impact on SLW cloud distribution.

scholarly journals Ground-based observations of cloud and drizzle liquid water path in stratocumulus clouds

2020 ◽  
Vol 13 (3) ◽  
pp. 1485-1499 ◽  
Author(s):  
Maria P. Cadeddu ◽  
Virendra P. Ghate ◽  
Mario Mech
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Precipitable Water ◽  
Cloud Base ◽  
Radiative Cooling ◽  
Liquid Water Path ◽  
Cell Systems ◽  
Water Path ◽  
Closed Cell ◽  
Stratocumulus Clouds

Abstract. The partition of cloud and drizzle water path in precipitating clouds plays a key role in determining the cloud lifetime and its evolution. A technique to quantify cloud and drizzle water path by combining measurements from a three-channel microwave radiometer (23.8, 30, and 90 GHz) with those from a vertically pointing Doppler cloud radar and a ceilometer is presented. The technique is showcased using 1 d of observations to derive precipitable water vapor, liquid water path, cloud water path, drizzle water path below the cloud base, and drizzle water path above the cloud base in precipitating stratocumulus clouds. The resulting cloud and drizzle water path within the cloud are in good qualitative agreement with the information extracted from the radar Doppler spectra. The technique is then applied to 10 d each of precipitating closed and open cellular marine stratocumuli. In the closed-cell systems only ∼20 % of the available drizzle in the cloud falls below the cloud base, compared to ∼40 % in the open-cell systems. In closed-cell systems precipitation is associated with radiative cooling at the cloud top <-100Wm-2 and a liquid water path >200 g m−2. However, drizzle in the cloud begins to exist at weak radiative cooling and liquid water path >∼150 g m−2. Our results collectively demonstrate that neglecting scattering effects for frequencies at and above 90 GHz leads to overestimation of the total liquid water path of about 10 %–15 %, while their inclusion paves the path for retrieving drizzle properties within the cloud.

scholarly journals A new retrieval for cloud liquid water path using a ground-based microwave radiometer and measurements of cloud temperature

2001 ◽  
Vol 106 (D13) ◽  
pp. 14485-14500 ◽  
Author(s):  
James C. Liljegren ◽  
Eugene E. Clothiaux ◽  
Gerald G. Mace ◽  
Seiji Kato ◽  
Xiquan Dong
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Cloud Temperature ◽  
Cloud Liquid Water Path

scholarly journals Cloud liquid water path in the sub-Arctic region of Europe as derived from ground-based and space-borne remote observations

2018 ◽  
Author(s):  
Vladimir S. Kostsov ◽  
Anke Kniffka ◽  
Dmitry V. Ionov
Keyword(s):  
Liquid Water ◽  
Hydrological Cycle ◽  
Microwave Radiometer ◽  
Diurnal Variations ◽  
Joint Analysis ◽  
Climate Modelling ◽  
Liquid Water Path ◽  
Water Path ◽  
Diurnal Cycles ◽  
Northern Latitudes

Abstract. Tropospheric clouds are a very important component of the climate system and of the hydrological cycle in Arctic and sub-Arctic. Liquid water path (LWP) is one of the key parameters of clouds urgently needed for a variety of studies, including the snow cover and climate modelling at Northern latitudes. A joint analysis of the LWP values obtained from observations by the SEVIRI satellite instrument and from ground-based observations by the RPG‑HATPRO microwave radiometer near St.Petersburg, Russia (60N, 30E) has been made. The time period of selected datasets spans two years (December 2012–November 2014) excluding winter months, since the specific requirements to SEVIRI observations restrict measurements at Northern latitudes in winter when the solar zenith angle is too large. The radiometer measurement site is located very close to the shore of the Gulf of Finland, and the SEVIRI measurements have shown considerable differences between the LWP values over land and over water areas in the region under investigation. Therefore, special attention has been paid to the analysis of the LWP spatial distributions derived from SEVIRI observations at scales from 15 km to 150 km in the vicinity of St.Petersburg. A good agreement between the daily median LWP values obtained from the SEVIRI and the RPG-HATPRO observations has been shown: the RMS difference has been estimated as 0.016 kg m−2 for a warm season and 0.048 kg m−2 for a cold season. During seven months (February–May and August–October), the SEVIRI and the RPG-HATPRO instruments revealed similar diurnal variations of LWP, while considerable discrepancies between the diurnal variations obtained by the two instruments have been detected in June and July. The LWP diurnal cycles obtained from the RPG-HATPRO and the SEVIRI observations have been compared to the diurnal cycles derived from the reanalysis data.

scholarly journals A dataset of microphysical cloud parameters, retrieved from Emission-FTIR spectra measured in Arctic summer 2017

2021 ◽  
Author(s):  
Philipp Richter ◽  
Mathias Palm ◽  
Christine Weinzierl ◽  
Hannes Griesche ◽  
Penny M. Rowe ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Infrared Spectra ◽  
Liquid Water ◽  
Microwave Radiometer ◽  
The Arctic ◽  
Liquid Water Path ◽  
Water Path ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Infrared Spectral

Abstract. A dataset of microphysical cloud parameters from optically thin clouds, retrieved from infrared spectral radiances measured in summer 2017 in the Arctic, is presented. Measurements were conducted using a mobile Fourier-transform infrared (FTIR) spectrometer which was carried by the RV Polarstern. This dataset contains retrieved optical depths and effective radii of ice and water, from which the liquid water path and ice water path are calculated. These water paths and the effective radii are compared with derived quantities from a combined cloud radar, lidar and microwave radiometer measurement synergy retrieval, called Cloudnet. Comparing the liquid water paths from the infrared retrieval and Cloudnet shows significant correlations with a standard deviation of 8.60 g · m−2. Although liquid water path retrievals from microwave radiometer data come with a uncertainty of at least 20 g · m−2, a significant correlation and a standard deviation of 5.32 g · m−2 between the results of clouds with a liquid water path of at most 20 g · m−2 retrieved from infrared spectra and results from Cloudnet can be seen. Therefore, despite its large uncertainty, the comparison with data retrieved from infrared spectra shows that optically thin clouds of the measurement campaign in summer 2017 can be observed well using microwave radiometers within the Cloudnet framework. Apart from this, the dataset of microphysical cloud properties presented here allows to perform calculations of the cloud radiative effects, when the Cloudnet data from the campaign are not available, which was from the 22nd July 2017 until the 19th August 2017. The dataset is published at Pangaea (Richter et al., 2021).

scholarly journals Cloud liquid water path in the sub-Arctic region of Europe as derived from ground-based and space-borne remote observations

2018 ◽  
Vol 11 (10) ◽  
pp. 5439-5460 ◽  
Author(s):  
Vladimir S. Kostsov ◽  
Anke Kniffka ◽  
Dmitry V. Ionov
Keyword(s):  
Liquid Water ◽  
Hydrological Cycle ◽  
Microwave Radiometer ◽  
Diurnal Variations ◽  
The Arctic ◽  
Joint Analysis ◽  
Climate Modelling ◽  
Liquid Water Path ◽  
Water Path ◽  
Northern Latitudes

Abstract. Tropospheric clouds are a very important component of the climate system and the hydrological cycle in the Arctic and sub-Arctic. Liquid water path (LWP) is one of the key parameters of clouds urgently needed for a variety of studies, including the snow cover and climate modelling at northern latitudes. A joint analysis was made of the LWP values obtained from observations by the SEVIRI satellite instrument and from ground-based observations by the RPG-HATPRO microwave radiometer near St Petersburg, Russia (60∘ N, 30∘ E). The time period of selected data sets spans 2 years (December 2012–November 2014) excluding winter months, since the specific requirements for SEVIRI observations restrict measurements at northern latitudes in winter when the solar zenith angle is too large. The radiometer measurement site is located very close to the shore of the Gulf of Finland, and our study has revealed considerable differences between the LWP values obtained by SEVIRI over land and over water areas in the region under investigation. Therefore, special attention was paid to the analysis of the LWP spatial distributions derived from SEVIRI observations at scales from 15 to 150 km in the vicinity of St Petersburg. Good agreement between the daily median LWP values obtained from the SEVIRI and the RPG-HATPRO observations was shown: the rms difference was estimated at 0.016 kg m−2 for a warm season and 0.048 kg m−2 for a cold season. Over 7 months (February–May and August–October), the SEVIRI and the RPG-HATPRO instruments revealed similar diurnal variations in LWP, while considerable discrepancies between the diurnal variations obtained by the two instruments were detected in June and July. On the basis of reanalysis data, it was shown that the LWP diurnal cycles are characterised by considerable interannual variability.

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