A 10 year climatology of cloud fraction and vertical distribution derived from both surface and GOES observations over the DOE ARM SPG site

Abstract

[1] Analysis of one decade of radar-lidar and Geostationary Operational Environmental Satellite (GOES) observations at the Department of Energy (DOE) Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) site reveals that there is excellent agreement in the long-term mean cloud fractions (CFs) derived from the surface and GOES data, and the CF is independent of temporal resolution and spatial scales for grid boxes of size 0.5°to 2.5°. When computed over a a 0.5 h (4 h) period, cloud frequency of occurrence (FREQ) and amount when present (AWP) derived from the point surface data agree very well with the same quantities determined from GOES for a 0.5°(2.5°) region centered on the DOE ARM SGP site. The values of FREQ (AWP) derived from the radar-lidar observations at a given altitude increase (decrease) as the averaging period increases from 5 min to 6 h. Similarly, CF at a given altitude increases as the vertical resolution increases from 90 to 1000 m. The profiles of CF have distinct bimodal vertical distributions, with a lower peak between 1 and 2 km and a higher one between 8 and 11 km. The 10 year mean total CF, 46.9%, varies seasonally from a summer minimum of 39.8% to a maximum of 54.6% during the winter. The annual mean CF is 1%-2% less than that from previous studies, ∼48%-49%, because fewer clouds occurred during 2005 and 2006, especially during winter. The differences in single-and multilayered CFs between this study and an earlier analysis can be explained by the different temporal resolutions used in the two studies, where single-layered CFs decrease but multilayered CFs increase from a 5 min resolution to a 1 h resolution. The vertical distribution of nighttime GOES high cloud tops agrees well with surface observations, but during the daytime, fewer high clouds are retrieved by the GOES analysis than seen from the surface observations. The FREQs for both daytime and nighttime GOES low cloud tops are significantly higher than surface observations, but the CFs are in good agreement.Citation: Xi, B., X. Dong, P. Minnis, and M. M. Khaiyer (2010), A 10 year climatology of cloud fraction and vertical distribution derived from both surface and GOES observations over the DOE ARM SPG site,

Fast simulators for satellite cloud optical centroid pressure retrievals; evaluation of OMI cloud retrievals

“…Over land, the CloudSat OCP PDF is bimodal with peaks near 400 and 600 hPa. Similar bimodal distributions of cloud top pressure and vertical structure have been shown with both active and passive sounding data as well as in general circulation model output (e.g., Chang and Li, 2005a,b;Comstock and Jakob, 2004;Mote and Frey, 2006;Xi et al, 2010). Neither OMI algorithm produces a bimodal distribution; both produce a single peak between 650 and 700 hPa.…”

Failure and Redemption of Multifilter Rotating Shadowband Radiometer (MFRSR)/Normal Incidence Multifilter Radiometer (NIMFR) Cloud Screening: Contrasting Algorithm Performance at Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) and Southern Great Plains (SGP) Sites

“…Performance of the original cloud-screening algorithms at the SGP site is illustrated in Figure 7 Different types of mid-latitude continental clouds have been observed at the SGP site from both the surface and space [26,27] and the original algorithms remove cloud-contaminated points successfully ( Figure 7). The agreement between PDFs of AOD generated by the original and improved cloud-screening algorithms (Figure 8) is consistent and shows that the improved version retains the performance of the standard algorithms [12,16] at the SGP site, even for partly cloudy days with large variety of cloud types.…”

Contribution to the development of DOE ARM Climate Modeling Best Estimate Data (CMBE) products: Satellite data over the ARM permanent and AMF sites: Final Report

“…Because an independent data source and longer time period are required to perform the evaluation, therefore we used MACE PI products at the SGP site in this study [4][5][6] [8]. Figure 5 shows the data availability for both CLDRAD and MACE PI products.…”

“…The details about the data qualities are discussed in a number of publications [1][2] [3]. The second dataset is the GOES VISST/SIST product over the four DOE ARM sites (SGP, MANUS, NAURU, and DARWIN) [4], and the third satellite dataset is the ISCCP data. Table 1 lists the ARM surface sites, the available satellite datasets, their availability time periods, and our delivering dates.…”