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Title: MODIS comparisons with northeastern Pacific in situ stratocumulus microphysics

Journal Article · · Journal of Geophysical Research: Atmospheres
DOI:https://doi.org/10.1002/2014JD022785· OSTI ID:1221674
 [1];  [1]
  1. Desert Research Institute Nevada System of Higher Education Reno Nevada USA
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Abstract Vertical sounding measurements within stratocumuli during two aircraft field campaigns, Marine Stratus/stratocumulus Experiment (MASE) and Physics of Stratocumulus Top (POST), are used to validate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical thickness (COT), cloud liquid water path (LWP), and cloud effective radius ( r e ). In situ COT, LWP, and r e were calculated using 5 m vertically averaged droplet probe measurements of complete vertical cloud penetrations. MODIS COT, LWP, and r e 1 km pixels were averaged along these penetrations. COT comparisons in POST showed strong correlations and a near 1:1 relationship. In MASE, comparisons showed strong correlations; however, MODIS COT exceeded in situ COT, likely due to larger temporal differences between MODIS and in situ measurements. LWP comparisons between two cloud probes show good agreement for POST but not MASE, giving confidence to POST data. Both projects provided strong LWP correlations but MODIS exceeded in situ by 14–36%. MODIS in situ r e correlations were strong, but MODIS 2.1 µm r e exceeded in situ r e , which contributed to LWP bias; in POST, MODIS r e was 20–30% greater than in situ r e . Maximum in situ r e near cloud top showed comparisons nearer 1:1. Other MODIS r e bands (3.7 µm and 1.6 µm) showed similar comparisons. Temporal differences between MODIS and in situ measurements, airplane speed differences, and cloud probe artifacts were likely causes of weaker MASE correlations. POST COT comparison was best for temporal differences under 20 min. POST data validate MODIS COT but it also implies a positive MODIS r e bias that propagates to LWP while still capturing variability.

Research Organization:
Univ. of Nevada, Reno, NV (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
DE‐FG02‐05ED63999; DE‐SC0009162; SC0009162
OSTI ID:
1221674
Alternate ID(s):
OSTI ID: 1221675; OSTI ID: 1454437
Journal Information:
Journal of Geophysical Research: Atmospheres, Journal Name: Journal of Geophysical Research: Atmospheres Vol. 120 Journal Issue: 16; ISSN 2169-897X
Publisher:
American Geophysical Union (AGU)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 21 works
Citation information provided by
Web of Science

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Related Subjects

54 ENVIRONMENTAL SCIENCES
remote sensing validation
stratocumulus optical depth
stratocumulus effective radius
cloud liquid water path
northeastern Pacific stratocumulus
cloud microphysics