 |
| Titel |
A spectral method for discriminating thermodynamic phase and retrieving cloud optical thickness and effective radius using transmitted solar radiance spectra |
| VerfasserIn |
S. E. LeBlanc, P. Pilewskie, K. S. Schmidt, O. Coddington |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-20), S.1361-1383 |
| Datensatznummer |
250116222
|
| Publikation (Nr.) |
 copernicus.org/amt-8-1361-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| A new retrieval scheme for cloud optical thickness, effective
radius, and thermodynamic phase was developed for ground-based
measurements of cloud shortwave solar spectral transmittance. Fifteen
parameters were derived to quantify spectral variations in shortwave
transmittance due to absorption and scattering of liquid water and
ice clouds, manifested by shifts in spectral slopes, curvatures,
maxima, and minima. To retrieve cloud optical thickness and
effective particle radius, a weighted least square fit that matched
the modeled parameters was applied. The measurements for this
analysis were made with the ground-based Solar Spectral Flux
Radiometer in Boulder, Colorado, between May 2012 and
January 2013. We compared the cloud optical thickness and effective
radius from the new retrieval to two other retrieval methods. By
using multiple spectral features, we find a closer fit (with a root
mean square difference over the entire spectra of 3.1% for
a liquid water cloud and 5.9% for an ice cloud) between
measured and modeled spectra compared to two other retrieval
methods which diverge by a root mean square of up to 6.4%
for a liquid water cloud and 22.5% for an ice cloud. The new
retrieval introduced here has an average uncertainty in effective
radius (± 1.2 μm) smaller by factor of at least 2.5
than two other methods when applied to an ice cloud. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|