scholarly journals First Observations of Tracking Clouds Using Scanning ARM Cloud Radars

2014 ◽  
Vol 53 (12) ◽  
pp. 2732-2746 ◽  
Author(s):  
Paloma Borque ◽  
Pavlos Kollias ◽  
Scott Giangrande
Keyword(s):  
Great Plains ◽  
Temporal Evolution ◽  
Department Of Energy ◽  
High Temporal Resolution ◽  
Advantages And Disadvantages ◽  
Weather Radars ◽  
Maximum Reflectivity ◽  
Cloud Properties ◽  
Atmospheric Radiation Measurement ◽  
Size Threshold

AbstractTracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large-drop formation (weather radar “first echo”). These measurements also complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2D) along-wind range–height indicator observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning Atmospheric Radiation Measurement Program (ARM) cloud radar (SACR) at the U.S. Department of Energy (DOE)–ARM Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger-scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous small nonprecipitating cloud elements. A new cloud identification and tracking algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2D observations (30 s) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud-element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived nonprecipitating clouds having an apparent life cycle shorter than 15 min. The advantages and disadvantages of cloud tracking using an SACR are discussed.

scholarly journals Sky cover from MFRSR observations

2011 ◽  
Vol 4 (7) ◽  
pp. 1463-1470 ◽  
Author(s):  
E. Kassianov ◽  
J. C. Barnard ◽  
L. K. Berg ◽  
C. Flynn ◽  
C. N. Long
Keyword(s):  
Great Plains ◽  
Visible Spectral Range ◽  
Department Of Energy ◽  
Research Facility ◽  
Southern Great Plains ◽  
Clear Sky ◽  
The Us ◽  
Atmospheric Radiation Measurement ◽  
Main Components ◽  
Good Agreement

Abstract. The diffuse all-sky surface irradiances measured at two nearby wavelengths in the visible spectral range and their modeled clear-sky counterparts are the main components of a new method for estimating the fractional sky cover of different cloud types, including cumuli. The performance of this method is illustrated using 1-min resolution data from a ground-based Multi-Filter Rotating Shadowband Radiometer (MFRSR). The MFRSR data are collected at the US Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site during the summer of 2007 and represent 13 days with cumuli. Good agreement is obtained between estimated values of the fractional sky cover and those provided by a well-established independent method based on broadband observations.

scholarly journals Retrieval of aerosol optical depth in vicinity of broken clouds from reflectance ratios: case study

2010 ◽  
Vol 3 (5) ◽  
pp. 1333-1349 ◽  
Author(s):  
E. Kassianov ◽  
M. Ovchinnikov ◽  
L. K. Berg ◽  
S. A. McFarlane ◽  
C. Flynn ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Great Plains ◽  
Land Surface ◽  
Single Layer ◽  
Department Of Energy ◽  
High Spectral Resolution ◽  
Data Sets ◽  
Atmospheric Radiation Measurement

Abstract. A recently developed reflectance ratio (RR) method for the retrieval of aerosol optical depth (AOD) is evaluated using extensive airborne and ground-based data sets collected during the Cloud and Land Surface Interaction Campaign (CLASIC) and the Cumulus Humilis Aerosol Processing Study (CHAPS), which took place in June 2007 over the US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains site. A detailed case study is performed for a field of single-layer shallow cumuli observed on 12 June 2007. The RR method is applied to retrieve the spectral values of AOD from the reflectance ratios measured by the MODIS Airborne Simulator (MAS) for two pairs of wavelengths (660 and 470 nm, 870 and 470 nm) collected at a spatial resolution of 0.05 km. The retrieval is compared with an independent AOD estimate from three ground-based Multi-filter Rotating Shadowband Radiometers (MFRSRs). The interpolation algorithm that is used to project MFRSR point measurements onto the aircraft flight tracks is tested using AOD derived from NASA Langley High Spectral Resolution Lidar (HSRL). The RR AOD estimates are in a good agreement (within 5%) with the MFRSR-derived AOD values for the 660-nm wavelength. The AODs obtained from MAS reflectance ratios overestimate those derived from MFRSR measurements by 15–30% for the 470-nm wavelength and underestimate the 870-nm AOD by the same amount.

scholarly journals Retrieval of aerosol optical depth in vicinity of broken clouds from reflectance ratios: case study

2010 ◽  
Vol 3 (2) ◽  
pp. 1889-1932
Author(s):  
E. Kassianov ◽  
M. Ovchinnikov ◽  
L. K. Berg ◽  
S. A. McFarlane ◽  
C. Flynn ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Great Plains ◽  
Land Surface ◽  
Single Layer ◽  
Department Of Energy ◽  
High Spectral Resolution ◽  
Data Sets ◽  
Atmospheric Radiation Measurement

Abstract. A recently developed reflectance ratio (RR) method for the retrieval of aerosol optical depth (AOD) is evaluated using extensive airborne and ground-based data sets collected during the Cloud and Land Surface Interaction Campaign (CLASIC) and the Cumulus Humilis Aerosol Processing Study (CHAPS), which took place in June 2007 over the US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains site. A detailed case study is performed for a field of single-layer shallow cumuli observed on 12 June 2007. The RR method is applied to retrieve the spectral values of AOD from the reflectance ratios measured by the MODIS Airborne Simulator (MAS) for two pairs of wavelengths (660 and 470 nm and 870 and 470 nm) collected at a spatial resolution of 0.05 km. The retrieval is compared with an independent AOD estimate from three ground-based Multi-filter Rotating Shadowband Radiometers (MFRSRs). The interpolation algorithm that is used to project MFRSR point measurements onto the aircraft flight tracks is tested using AOD derived from NASA Langley High Spectral Resolution Lidar (HSRL). The RR AOD estimates are in a good agreement (within 5%) with the MFRSR-derived AOD values for the 660-nm wavelength. The AODs obtained from MAS reflectance ratios overestimate those derived from MFRSR measurements by 15–30% for the 470-nm wavelength and underestimate the 870-nm AOD by the same amount.

scholarly journals Sky cover from MFRSR observations: cumulus clouds

2011 ◽  
Vol 4 (1) ◽  
pp. 715-735 ◽  
Author(s):  
E. Kassianov ◽  
J. Barnard ◽  
L. K. Berg ◽  
C. Flynn ◽  
C. N. Long
Keyword(s):  
Great Plains ◽  
Visible Spectral Range ◽  
Department Of Energy ◽  
Cumulus Clouds ◽  
Southern Great Plains ◽  
Clear Sky ◽  
The Us ◽  
Atmospheric Radiation Measurement ◽  
Main Components ◽  
Good Agreement

Abstract. The diffuse all-sky surface irradiances measured at two nearby wavelengths in the visible spectral range and their model clear-sky counterparts are two main components of a new method for estimating the fractional sky cover of different cloud types, including cumulus clouds. The performance of this method is illustrated using 1-min resolution data from ground-based Multi-Filter Rotating Shadowband Radiometer (MFRSR). The MFRSR data are collected at the US Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site during the summer of 2007 and represent 13 days with cumulus clouds. Good agreement is obtained between estimated values of the fractional sky cover and those provided by a well-established independent method based on broadband observations.

Evaluation of a land-atmosphere coupling metric computed from a ground-based infrared interferometer

2021 ◽  
Author(s):  
Ryann A. Wakefield ◽  
David D. Turner ◽  
Jeffrey B. Basara
Keyword(s):  
Great Plains ◽  
Land Surface ◽  
Surface Flux ◽  
Observation Time ◽  
High Temporal Resolution ◽  
Vertical Profiles ◽  
Sensing Platforms ◽  
Humidity Index ◽  
Atmospheric Radiation Measurement ◽  
Meteorological Observations

AbstractLand-atmosphere feedbacks are a critical component of the hydrologic cycle. Vertical profiles of boundary layer temperature and moisture, together with information about the land surface, are used to compute land-atmosphere coupling metrics. Ground based remote sensing platforms, such as the Atmospheric Emitted Radiance Interferometer (AERI), can provide high temporal resolution vertical profiles of temperature and moisture. When co-located with soil moisture, surface flux, and surface meteorological observations, such as at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site, it is possible to observe both the terrestrial and atmospheric legs of land-atmosphere feedbacks. In this study, we compare a commonly used coupling metric computed from radiosonde-based data to that obtained from the AERI to characterize the accuracy and uncertainty in the metric derived from the two distinct platforms. This approach demonstrates the AERI’s utility where radiosonde observations are absent in time and/or space. Radiosonde and AERI based observations of the Convective Triggering Potential and Low-Level Humidity Index (CTP-HIlow) were computed during the 1200 UTC observation time and displayed good agreement during both 2017 and 2019 warm seasons. Radiosonde and AERI derived metrics diagnosed the same atmospheric preconditioning based upon the CTP-HIlow framework a majority of the time. When retrieval uncertainty was considered, even greater agreement was found between radiosonde and AERI derived classification. The AERI’s ability to represent this coupling metric well enabled novel exploration of temporal variability within the overnight period in CTP and HIlow. Observations of CTP-HIlow computed within a few hours of 1200 UTC were essentially equivalent, however with greater differences in time arose greater differences in CTP and HIlow.

scholarly journals Erroneous Attribution of Deep Convective Invigoration to Aerosol Concentration

2018 ◽  
Vol 75 (4) ◽  
pp. 1351-1368 ◽  
Author(s):  
Adam Varble
Keyword(s):  
Great Plains ◽  
Convective Available Potential Energy ◽  
Meteorological Factor ◽  
Department Of Energy ◽  
Cloud Base ◽  
Neutral Buoyancy ◽  
Aerosol Effect ◽  
Surface Condensation ◽  
Atmospheric Radiation Measurement ◽  
Upper Level

Abstract Contiguous time–height cloud objects at the Department of Energy Atmospheric Radiation Measurement Southern Great Plains (SGP) site are matched with surface condensation nuclei (CN) concentrations and retrieved thermodynamic and kinematic vertical profiles for warm-cloud-base, cold-cloud-top systems in convectively unstable environments. Statistical analyses show that previously published conclusions that increasing CN concentrations cause a decrease in minimum cloud-top temperature (CTT) at the SGP site through the aerosol convective invigoration effect are unfounded. The CN–CTT relationship is statistically insignificant, while correlations between convective available potential energy (CAPE), level of neutral buoyancy (LNB), and CN concentration account for most of the change in the CN–CTT positive correlation. Removal of clouds with minimum CTTs > −36°C from the analysis eliminates the CN–CTT correlation. Composited dirty conditions at the SGP have ~1°C-warmer low levels and ~1°C-cooler upper levels than clean conditions. This correlation between aerosol concentrations and thermodynamic profiles may be caused by an increase in regional rainfall preceding deep convective conditions as CN concentration decreases. Increased rainfall can be expected to increase wet deposition of aerosols, cool low-level temperatures, and warm upper-level temperatures. The masking of a potential aerosol effect by such small thermodynamic changes implies that the strategy of analyzing subsets of aerosol data by binned meteorological factor values is not a valid method for discerning an aerosol effect in some situations. These findings highlight the need for more careful, detailed, and strategic observations to confidently isolate and quantify an aerosol deep convective invigoration effect.

scholarly journals Ground-based all-sky mid-infrared and visible imagery for purposes of characterizing cloud properties

2014 ◽  
Vol 7 (2) ◽  
pp. 637-645 ◽  
Author(s):  
D. I. Klebe ◽  
R. D. Blatherwick ◽  
V. R. Morris
Keyword(s):  
Great Plains ◽  
Precipitable Water ◽  
Mid Infrared ◽  
Cloud Properties ◽  
Cloud Height ◽  
Calibration Methods ◽  
Cloud Temperature ◽  
Atmospheric Radiation Measurement ◽  
Community Data ◽  
And Performance

Abstract. This paper describes the All Sky Infrared Visible Analyzer (ASIVA), a multi-purpose visible and infrared sky imaging and analysis instrument whose primary function is to provide radiometrically calibrated imagery in the mid-infrared (mid-IR) atmospheric window. This functionality enables the determination of diurnal fractional sky cover and estimates of sky/cloud temperature from which one can derive estimates of sky/cloud emissivity and cloud height. This paper describes the calibration methods and performance of the ASIVA instrument with particular emphasis on data products being developed for the meteorological community. Data presented here were collected during the Solmirus' ASIVA campaign conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility from 21 May to 27 July 2009. The purpose of this campaign was to determine the efficacy of IR technology in providing reliable nighttime sky cover data. Significant progress has been made in the analysis of the campaign data over the past several years and the ASIVA has proven to be an excellent instrument for determining sky cover as well as the potential for determining sky/cloud temperature, sky/cloud emissivity, precipitable water vapor (PWV), and ultimately cloud height.

scholarly journals Cloud Area Distributions of Shallow Cumuli: A New Method for Ground-Based Images

Atmosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 258 ◽  
Author(s):  
Jessica Kleiss ◽  
Erin Riley ◽  
Charles Long ◽  
Laura Riihimaki ◽  
Larry Berg ◽  
...  
Keyword(s):  
Great Plains ◽  
Single Layer ◽  
Cloud Base ◽  
High Temporal Resolution ◽  
Equivalent Diameter ◽  
Spatial And Temporal Patterns ◽  
Convective Boundary ◽  
Wide Range ◽  
Lidar Measurements ◽  
Atmospheric Radiation Measurement

We develop a new approach that resolves cloud area distributions of single-layer shallow cumuli from ground-based observations. Our simple and computationally inexpensive approach uses images obtained from a Total Sky Imager (TSI) and complementary information on cloud base height provided by lidar measurements to estimate cloud equivalent diameter (CED) over a wide range of cloud sizes (about 0.01–3.5 km) with high temporal resolution (30 s). We illustrate the feasibility of our approach by comparing the estimated CEDs with those derived from collocated and coincident high-resolution (0.03 km) Landsat cloud masks with different spatial and temporal patterns of cloud cover collected over the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site. We demonstrate that (1) good (~7%) agreement between TSI and Landsat characteristic cloud size can be obtained for clouds that fall within the region of the sky observable by the TSI and (2) large clouds that extend beyond this region are responsible for noticeable (~16%) underestimation of the TSI characteristic cloud size. Our approach provides a previously unavailable dataset for process studies in the convective boundary layer and evaluation of shallow cumuli in cloud-resolving models.

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