scholarly journals The characterization of deep convective cloud albedo as a calibration target using MODIS reflectances

2010 ◽  
Author(s):  
David R. Doelling ◽  
Gang Hong ◽  
Dan Morstad ◽  
Rajendra Bhatt ◽  
Arun Gopalan ◽  
...  
Keyword(s):  
Convective Cloud ◽  
Calibration Target ◽  
Cloud Albedo ◽  
Deep Convective Cloud

scholarly journals Characteristics of the raindrop distributions in RICO shallow cumulus

2014 ◽  
Vol 14 (1) ◽  
pp. 677-705 ◽  
Author(s):  
O. Geoffroy ◽  
A. P. Siebesma ◽  
F. Burnet
Keyword(s):  
Shape Parameter ◽  
Convective Cloud ◽  
Ground Level ◽  
Number Concentration ◽  
Shape Parameters ◽  
Shallow Cumulus ◽  
Gamma Law ◽  
Deep Convective Cloud

Abstract. The physical properties of rain spectra are generally modeled using analytical distribution, commonly the Gamma law and to a lesser extent the Lognormal law. The majority of studies of the literature focusing on the characterization of rain distribution are based on deep convective cloud observations, mostly at ground level. This study focuses on shallow cumulus rain distribution at every level in the cloudy boundary layer using airborne in situ measurements made with both the PMS-OAP-260X and the PMS-2DP instruments during the RICO field experiment. Sampled spectra analyzed at the scale of LES resolution (100 m) are found to be relatively broad, with values of the shape parameter – υ for the Gamma law and σg for the Lognormal law, respectively – of the order of 1–3 and 1.5–2. The dependence of the shape parameters on the rain variable is examined, and a parameterization of the shape parameters υ and σg in function of a power law of the rainwater content and raindrop number concentration is proposed.

scholarly journals Radiometric Performance Evaluation of FY-4A/AGRI Based on Aqua/MODIS

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1859
Author(s):  
Bo Zhong ◽  
Yingbo Ma ◽  
Aixia Yang ◽  
Junjun Wu
Keyword(s):  
Near Infrared ◽  
Spectral Response ◽  
Convective Cloud ◽  
Radiation Level ◽  
High Attenuation ◽  
Total Attenuation ◽  
Attenuation Rate ◽  
Calibration Facility ◽  
Deep Convective Cloud ◽  
Directional Reflectance

Fengyun-4A (FY-4A) is the first satellite of the Chinese second-generation geostationary orbit meteorological satellites (FY-4). The Advanced Geostationary Radiation Imager (AGRI), onboard FY-4A does not load with high-precision calibration facility in visible and near infrared (VNIR) channel. As a consequence, it is necessary to comprehensively evaluate its radiometric performance and quantitatively describe the attenuation while using its VNIR data. In this paper, the radiometric performance at VNIR channels of FY-4A/AGRI is evaluated based on Aqua/MODIS data using the deep convective cloud (DCC) target. In order to reduce the influence of view angle and spectral response difference, the bi-directional reflectance distribution function (BRDF) correction and spectral matching have been performed. The evaluation result shows the radiometric performance of FY-4A/AGRI: (1) is less stable and with obvious fluctuations; (2) has a lower radiation level because of 24.99% lower compared with Aqua/MODIS; 3) has a high attenuation with 9.11% total attenuation over 2 years and 4.0% average annual attenuation rate. After the evaluation, relative radiometric normalization between AGRI and MODIS in VNIR channel is performed and the procedure is proved effective. This paper proposed a more reliable reference for the quantitative applications of FY-4A data.

scholarly journals How do changes in warm-phase microphysics affect deep convective clouds?

2017 ◽  
Vol 17 (15) ◽  
pp. 9585-9598 ◽  
Author(s):  
Qian Chen ◽  
Ilan Koren ◽  
Orit Altaratz ◽  
Reuven H. Heiblum ◽  
Guy Dagan ◽  
...  
Keyword(s):  
Rain Rate ◽  
Convective Cloud ◽  
Cloud Fraction ◽  
Marshall Islands ◽  
Cloud System ◽  
Main Question ◽  
Convective Clouds ◽  
Deep Convective Clouds ◽  
Aerosol Effects ◽  
Deep Convective Cloud

Abstract. Understanding aerosol effects on deep convective clouds and the derived effects on the radiation budget and rain patterns can largely contribute to estimations of climate uncertainties. The challenge is difficult in part because key microphysical processes in the mixed and cold phases are still not well understood. For deep convective clouds with a warm base, understanding aerosol effects on the warm processes is extremely important as they set the initial and boundary conditions for the cold processes. Therefore, the focus of this study is the warm phase, which can be better resolved. The main question is: How do aerosol-derived changes in the warm phase affect the properties of deep convective cloud systems? To explore this question, we used a weather research and forecasting (WRF) model with spectral bin microphysics to simulate a deep convective cloud system over the Marshall Islands during the Kwajalein Experiment (KWAJEX). The model results were validated against observations, showing similarities in the vertical profile of radar reflectivity and the surface rain rate. Simulations with larger aerosol loading resulted in a larger total cloud mass, a larger cloud fraction in the upper levels, and a larger frequency of strong updrafts and rain rates. Enlarged mass both below and above the zero temperature level (ZTL) contributed to the increase in cloud total mass (water and ice) in the polluted runs. Increased condensation efficiency of cloud droplets governed the gain in mass below the ZTL, while both enhanced condensational and depositional growth led to increased mass above it. The enhanced mass loading above the ZTL acted to reduce the cloud buoyancy, while the thermal buoyancy (driven by the enhanced latent heat release) increased in the polluted runs. The overall effect showed an increased upward transport (across the ZTL) of liquid water driven by both larger updrafts and larger droplet mobility. These aerosol effects were reflected in the larger ratio between the masses located above and below the ZTL in the polluted runs. When comparing the net mass flux crossing the ZTL in the clean and polluted runs, the difference was small. However, when comparing the upward and downward fluxes separately, the increase in aerosol concentration was seen to dramatically increase the fluxes in both directions, indicating the aerosol amplification effect of the convection and the affected cloud system properties, such as cloud fraction and rain rate.

scholarly journals Randomized convective cloud seeding experiment in extended areas in Cuba (EXPAREX)

2011 ◽  
Vol 26 (4) ◽  
pp. 515-528 ◽  
Author(s):  
Daniel Martinez-Castro ◽  
Carlos A Pérez-Sanchez ◽  
Boris P Koloskov ◽  
Victor V. Korneev ◽  
Victor V Petrov ◽  
...  
Keyword(s):  
Experimental Design ◽  
Rainy Season ◽  
Convective Cloud ◽  
General Description ◽  
Cloud Seeding ◽  
Design Procedures ◽  
Successful Experiment ◽  
Randomization Scheme ◽  
Confirmatory Phase

The Randomized Convective Cloud Seeding Experiment in Extended Areas (EXPerimento aleatorizado de siembra de nubes en AReas EXtensas, EXPAREX) is being implemented in Camagüey, Cuba and adjacent regions from August 2005 as the continuation of a previous successful experiment (PCMAT), held in the period 1982-1990. The first season of the experiment was exploratory and was focused on upgrading facilities, equipment and software, including an An-26 instrumented aircraft and the 10-cm MRL-5 weather radar. It was aimed at implementing methodologies and testing the application of the experimental design, excluding the randomization scheme, which was scheduled to be started in the second experimental year, in the rainy season of 2006. The field operations of the confirmatory phase started only in October, 2006, when seven experimental units, treated under a randomized scheme, were qualified. In the 2007 experiment, 13 more experimental units were processed. The general description, experimental design, procedures and characterization of the first two experimental seasons of the confirmatory phase of EXPAREX are presented in this work. Is it shown that the experimental clouds processed in the first two seasons of the experiment have similar characteristics to the PCMAT clouds, so that the conclusions of previous physical research are applicable.

Assessment of MODIS on-orbit calibration using a deep convective cloud technique

2016 ◽  
Author(s):  
Qiaozhen Mu ◽  
Aisheng Wu ◽  
Tiejun Chang ◽  
Amit Angal ◽  
Daniel Link ◽  
...  
Keyword(s):  
Convective Cloud ◽  
Deep Convective Cloud

Design and Characterization of a Peltier-Cold Calibration Target for a 110-GHz Radiometer

2015 ◽  
Vol 53 (1) ◽  
pp. 344-351 ◽  
Author(s):  
Susana Fernandez ◽  
Axel Murk ◽  
Niklaus Kampfer
Keyword(s):  
Calibration Target
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