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E. O. Schmidt
,
R. F. Arduini
,
B. A. Wielicki
,
R. S. Stone
, and
S-C. Tsay

Abstract

Brightness temperature difference (BTD) values are calculated for selected Geostationary Operational Environmental Satellite (GOES-6) channels (3.9, 12.7 µm) and Advanced Very High Resolution Radiometer channels (3.7, 12.0 µm). Daytime and nighttime discrimination of particle size information is possible given the infrared cloud extinction optical depth and the BTD value. BTD values are presented and compared for cirrus clouds composed of equivalent ice spheres (volume, surface area) versus randomly oriented hexagonal ice crystals. The effect of the hexagonal ice crystals is to increase the magnitude of the BTD values calculated relative to equivalent ice sphere (volume, surface area) BTDs. Equivalent spheres (volume or surface area) do not do a very good job of modeling hexagonal ice crystal effects on BTDs; however, the use of composite spheres improves the simulation and offers interesting prospects. Careful consideration of the number of Legendre polynomial coefficients used to fit the scattering phase functions is crucial to realistic modeling of cirrus BTDs. Surface and view-angle effects are incorporated to provide more realistic simulation.

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S. Crewell
,
H. Bloemink
,
A. Feijt
,
S. G. García
,
D. Jolivet
,
O. A. Krasnov
,
A. van Lammeren
,
U. Löhnert
,
E. van Meijgaard
,
J. Meywerk
,
M. Quante
,
K. Pfeilsticker
,
S. Schmidt
,
T. Scholl
,
C. Simmer
,
M. Schröder
,
T. Trautmann
,
V. Venema
,
M. Wendisch
, and
U. Willén

Clouds cause uncertainties in the determination of climate sensitivity to either natural or anthropogenic changes. Furthermore, clouds dominate our perception of the weather, and the relatively poor forecast of cloud and precipitation parameters in numerical weather prediction (NWP) models is striking. In order to improve modeling and forecasting of clouds in climate and NWP models the BALTEX BRIDGE Campaign (BBC) was conducted in the Netherlands in August/September 2001 as a contribution to the main field experiment of the Baltic Sea Experiment (BALTEX) from April 1999 to March 2001 (BRIDGE). The complex cloud processes, which involve spatial scales from less than 1 mm (condensation nuclei) to 1000 km (frontal systems) require an integrated measurement approach. Advanced remote sensing instruments were operated at the central facility in Cabauw, Netherlands, to derive the vertical cloud structure. A regional network of stations was operated within a 100 km × 100 km domain to observe solar radiation, cloud liquid water path, cloud-base temperature, and height. Aircraft and tethered balloon measurements were used to measure cloud microphysical parameters and solar radiation below, in, and above the cloud. Satellite measurements complemented the cloud observations by providing the spatial structure from above. In order to better understand the effect of cloud inhomogeneities on the radiation field, three-dimensional radiative transfer modeling was closely linked to the measurement activities. To evaluate the performance of dynamic atmospheric models for the cloudy atmosphere four operational climate and NWP models were compared to the observations. As a first outcome of BBC we demonstrate that increased vertical resolution can improve the representation of clouds in these models.

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V. Masson-Delmotte
,
S. Hou
,
A. Ekaykin
,
J. Jouzel
,
A. Aristarain
,
R. T. Bernardo
,
D. Bromwich
,
O. Cattani
,
M. Delmotte
,
S. Falourd
,
M. Frezzotti
,
H. Gallée
,
L. Genoni
,
E. Isaksson
,
A. Landais
,
M. M. Helsen
,
G. Hoffmann
,
J. Lopez
,
V. Morgan
,
H. Motoyama
,
D. Noone
,
H. Oerter
,
J. R. Petit
,
A. Royer
,
R. Uemura
,
G. A. Schmidt
,
E. Schlosser
,
J. C. Simões
,
E. J. Steig
,
B. Stenni
,
M. Stievenard
,
M. R. van den Broeke
,
R. S. W. van de Wal
,
W. J. van de Berg
,
F. Vimeux
, and
J. W. C. White

Abstract

A database of surface Antarctic snow isotopic composition is constructed using available measurements, with an estimate of data quality and local variability. Although more than 1000 locations are documented, the spatial coverage remains uneven with a majority of sites located in specific areas of East Antarctica. The database is used to analyze the spatial variations in snow isotopic composition with respect to geographical characteristics (elevation, distance to the coast) and climatic features (temperature, accumulation) and with a focus on deuterium excess. The capacity of theoretical isotopic, regional, and general circulation atmospheric models (including “isotopic” models) to reproduce the observed features and assess the role of moisture advection in spatial deuterium excess fluctuations is analyzed.

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J. S. Reid
,
H. B. Maring
,
G. T. Narisma
,
S. van den Heever
,
L. Di Girolamo
,
R. Ferrare
,
P. Lawson
,
G. G. Mace
,
J. B. Simpas
,
S. Tanelli
,
L. Ziemba
,
B. van Diedenhoven
,
R. Bruintjes
,
A. Bucholtz
,
B. Cairns
,
M. O. Cambaliza
,
G. Chen
,
G. S. Diskin
,
J. H. Flynn
,
C. A. Hostetler
,
R. E. Holz
,
T. J. Lang
,
K. S. Schmidt
,
G. Smith
,
A. Sorooshian
,
E. J. Thompson
,
K. L. Thornhill
,
C. Trepte
,
J. Wang
,
S. Woods
,
S. Yoon
,
M. Alexandrov
,
S. Alvarez
,
C. G. Amiot
,
J. R. Bennett
,
M., Brooks
,
S. P. Burton
,
E. Cayanan
,
H. Chen
,
A. Collow
,
E. Crosbie
,
A. DaSilva
,
J. P. DiGangi
,
D. D. Flagg
,
S. W. Freeman
,
D. Fu
,
E. Fukada
,
M. R. A. Hilario
,
Y. Hong
,
S. M. Hristova-Veleva
,
R. Kuehn
,
R. S. Kowch
,
G. R. Leung
,
J. Loveridge
,
K. Meyer
,
R. M. Miller
,
M. J. Montes
,
J. N. Moum
,
Thanos Nenes
,
S. W. Nesbitt
,
M. Norgren
,
E. P. Nowottnick
,
R. M. Rauber
,
E. A. Reid
,
S. Rutledge
,
J. S. Schlosser
,
T. T. Sekiyama
,
M. A. Shook
,
G. A. Sokolowsky
,
S. A. Stamnes
,
T. Y. Tanaka
,
A. Wasilewski
,
P. Xian
,
Q. Xiao
,
Zhuocan Xu
, and
J. Zavaleta

Abstract

The NASA Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) employed the NASA P-3, Stratton Park Engineering Company (SPEC) Learjet 35, and a host of satellites and surface sensors to characterize the coupling of aerosol processes, cloud physics, and atmospheric radiation within the Maritime Continent’s complex southwest monsoonal environment. Conducted in the late summer of 2019 from Luzon Philippines in conjunction with the Office of Naval Research Propagation of Intraseasonal Tropical OscillatioNs (PISTON) experiment with its R/V Sally Ride stationed in the North Western Tropical Pacific, CAMP2Ex documented diverse biomass burning, industrial and natural aerosol populations and their interactions with small to congestus convection. The 2019 season exhibited El Nino and associated drought, high biomass burning emissions, and an early monsoon transition allowing for observation of pristine to massively polluted environments as they advected through intricate diurnal mesoscale and radiative environments into the monsoonal trough. CAMP2Ex’s preliminary results indicate 1) increasing aerosol loadings tend to invigorate congestus convection in height and increase liquid water paths; 2) lidar, polarimetry, and geostationary Advanced Himawari Imager remote sensing sensors have skill in quantifying diverse aerosol and cloud properties and their interaction; and 3) high resolution remote sensing technologies are able to greatly improve our ability to evaluate the radiation budget in complex cloud systems. Through the development of innovative informatics technologies, CAMP2Ex provides a benchmark dataset of an environment of extremes for the study of aerosol, cloud and radiation processes as well as a crucible for the design of future observing systems.

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