Macrophysical properties of continental shallow cumuli: diurnal evolution

Kassianov, Evgueni I.; Riley, Erin A.; Kleiss, Jessica M.; Riihimaki, Laura; Berg, Larry K.

doi:10.1117/12.2534359

Cited by 4 publications

(3 citation statements)

References 20 publications

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“…This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ Previous work has examined continental shallow Cu in different regions throughout the world, focusing mainly on the Southern Great Plains (SGP) [9], [11], [12], [14], [25], [26] and the Amazon basin [27]- [29]. Specifically, toward improving the representation of shallow Cu in GCMs and numerical weather prediction models, factors such as their cloud size distribution (CSD) and diurnal cycle, are being extensively studied.…”

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confidence: 99%

On the Abundance and Common Properties of Continental, Organized Shallow (Green) Clouds

Dror

Koren

Altaratz

et al. 2021

IEEE Trans. Geosci. Remote Sensing

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Warm convective clouds play a significant role in the earth's energy and water budgets. However, they still pose a challenge in climate research as their feedback to predicted thermodynamic changes is highly uncertain and considered critical to the overall climate system's response. The focus of this study is continental, organized shallow convective clouds that, although they are spread globally and form in a variety of environments, seem to have common properties. One of these properties seems to be their preferred formation over vegetated areas, thus referred hereafter as green Cu. In this article, we present new observations of emerging universality and explore them using a method that combines fine-and coarse-resolution remotesensing data sets. First, we use Moderate Resolution Imaging Spectroradiometer (MODIS) true-color images to visually classify cloud fields into different classes and identify green Cu fields. We show that the level and type of organization and the properties of these fields (e.g., cloud size distribution and cloud fraction) are similar throughout the world, regardless of their location. Second, we match the corresponding MODIS level-3 cloud properties to the identified cloud classes, and based on this data sets statistics, we develop a detection method for green Cu along ten years of measurements (2003-2012). We examine the geographical distribution and seasonality of this class and show that these fields are highly abundant over many continental areas and indeed mostly in the vicinity of vegetated regions.

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confidence: 99%

On the Abundance and Common Properties of Continental, Organized Shallow (Green) Clouds

Dror

Koren

Altaratz

et al. 2021

IEEE Trans. Geosci. Remote Sensing

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“…The US Southern Great Plains (SGP) region is a favorable spot to study continental ShCu owing to the long‐term co‐located observations of land surface, atmospheric boundary layer and clouds by the Department Of Energy (DOE) Atmospheric Radiation Measurement (ARM) program (Berg & Kassianov, 2008; Kassianov et al., 2019; Lamer & Kollias, 2015; Lareau et al., 2018; Qiu & Williams, 2020; Romps & Öktem, 2018; Q. Tang et al., 2018; S. Tang et al., 2019; Xiao et al., 2018; Zhang & Klein, 2010, 2013; Zhang et al., 2017). Tao et al.…”

Section: Introductionmentioning

confidence: 99%

How Does Land Cover and Its Heterogeneity Length Scales Affect the Formation of Summertime Shallow Cumulus Clouds in Observations From the US Southern Great Plains?

Tian

Zhang

Klein

et al. 2022

Geophysical Research Letters

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This study investigates the effects of heterogeneous land covers on shallow cumulus (ShCu) clouds at the US Southern Great Plains using high‐resolution satellite and land cover data. During late summer, ShCu occurs over cities the most frequently and over open waters the least frequently, and more often over forest than over grassland. The preferential occurrence of ShCu over forest relative to grassland is consistent with surface measurements showing larger heat fluxes over forests. This preferential occurrence also varies with the length scales of land patches with the largest cloud occurrence difference shifting from smaller length scales (<9 km) during midday to larger scales (>9 km) in the early afternoon. Consistent with theory, these signals are more pronounced under low wind conditions. The preferential length scale shift with time suggests the existence of secondary circulations that strengthen and promote convergence over larger spatial scales as the differential land surface heating intensifies.

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“…They are also important for their seeding role in transitioning into hot-tower deep convective clouds with heavy precipitation [7]. ShCu are small in horizontal extent, of around a few hundred meters to several kilometers, and they are short-lived, lasting 15 to 30 min from initiation to dissipation [8][9][10][11][12][13][14]. With such spatiotemporal scale, ShCu cannot be explicitly resolved, but are highly parameterized in climate models.…”

Section: Introductionmentioning

confidence: 99%

Summertime Continental Shallow Cumulus Cloud Detection Using GOES-16 Satellite and Ground-Based Stereo Cameras at the DOE ARM Southern Great Plains Site

et al. 2021

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Summertime continental shallow cumulus clouds (ShCu) are detected using Geostationary Operational Environmental Satellite (GOES)-16 reflectance data, with cross-validation by observations from ground-based stereo cameras at the Department of Energy Atmospheric Radiation Measurement Southern Great Plains site. A ShCu cloudy pixel is identified when the GOES reflectance exceeds the clear-sky surface reflectance by a reflectance detection threshold of ShCu, ΔR. We firstly construct diurnally varying clear-sky surface reflectance maps and then estimate the ∆R. A GOES simulator is designed, projecting the clouds reconstructed by stereo cameras towards the surface along the satellite’s slanted viewing direction. The dynamic ShCu detection threshold ΔR is determined by making the GOES cloud fraction (CF) equal to the CF from the GOES simulator. Although there are temporal variabilities in ΔR, cloud fractions and cloud size distributions can be well reproduced using a constant ΔR value of 0.045. The method presented in this study enables daytime ShCu detection, which is usually falsely reported as clear sky in the GOES-16 cloud mask data product. Using this method, a new ShCu dataset can be generated to bridge the observational gap in detecting ShCu, which may transition into deep precipitating clouds, and to facilitate further studies on ShCu development over heterogenous land surface.

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Macrophysical properties of continental shallow cumuli: diurnal evolution

Cited by 4 publications

References 20 publications

On the Abundance and Common Properties of Continental, Organized Shallow (Green) Clouds

On the Abundance and Common Properties of Continental, Organized Shallow (Green) Clouds

How Does Land Cover and Its Heterogeneity Length Scales Affect the Formation of Summertime Shallow Cumulus Clouds in Observations From the US Southern Great Plains?

Summertime Continental Shallow Cumulus Cloud Detection Using GOES-16 Satellite and Ground-Based Stereo Cameras at the DOE ARM Southern Great Plains Site

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