Getting Involved

The Science Team for the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite mission is organizing an international program to obtain correlative measurements to support validation of its retrieved products. Individuals or groups are invited to participate in intercomparison activities between CALIPSO and other ground-based, airborne, and satellite instruments. We are seeking investigators who may be collecting data within the troposphere and lower stratosphere as part of on-going research programs and would be interested in collaboration with the CALIPSO program.

CALIPSO is part of the NASA Office of Earth Science, Earth Systems Science Pathfinder (ESSP) Program. The CALIPSO mission is managed by the NASA Langley Research Center (LaRC) and is a partnership with the Centre National d’Etudes Spatiales (CNES). The primary goal of the CALIPSO mission is to provide global, high-spatial-resolution measurements of the vertical distribution and optical properties of tropospheric aerosols and clouds that will significantly improve our understanding of the effects of aerosols and clouds on the Earth’s radiation budget. CALIPSO will provide:

§         a means for the first observationally based estimates of direct aerosol forcing;
§         an improved empirical basis for assessing indirect aerosol forcing;
§         a factor of two improvement in the accuracy of satellite estimates of surface and atmospheric;
§         longwave radiative fluxes; and,
§         a new ability for assessing cloud-climate feedback.

CALIPSO will fly a 3-channel polarization sensitive lidar (532┴ nm, 532║ nm, and 1064 nm), imaging infrared radiometer (8.65 µm, 10.6 µm, 12.05 µm), and wide field camera, in formation with the Earth Observing System (EOS) Aqua, ESSP CloudSat, and AURA satellites, and the French Parasol and provide continuous, near-simultaneous measurements for a period of three years. CALIPSO is scheduled to be launched in April 2006.

Table 1 lists the retrieved data products that will be archived and made available at NASA's Atmospheric Science Data Center (ASDC) at the NASA Langley Research Center (http://eosweb.larc.nasa.gov). In order to assess and understand uncertainties in CALIPSO data products, our validation program seeks near-coincident in-situ and remotely-sensed correlative measurements relevant to CALIPSO observations during satellite overpasses throughout the lifetime of the mission.

Data Product

Measurement Capabilities and Uncertainties

Data Product Resolution

Horizontal

Vertical

Aerosols

Height, thickness

For layers with b > 2.5 x 10-4 km-1 sr-1

5km

60 m

Optical depth, t

40% *

5 km

N/A

Backscatter, b a(z)

20 - 30%

40 km

40 km

Z < 20 km 120 m

Z ³ 20 km: 360 m

Extinction, sa(z)

40 % *

40 km

40 km

z < 20 km  120 m

z ³ 20 km: 360 m

Clouds

Height

For layers with b > 1 x 10-3 km-1 sr-1

1/3, 1, 5 km

30, 60 m

Thickness

for layers with t < 5

1/3, 1, 5 km

30, 60 m

Optical depth, t

within a factor of 2 for t < 5

5 km

N/A

Backscatter, b c(z)

20 - 30%

5 km

60 m

Extinction, sc(z)

within a factor of 2 for t < 5

5 km

60 m

Ice/water phase

Layer by layer

5 km

60 m

Ice cloud emissivity, e

±0.03

1 km

N/A

Ice particle size

±50% for e > 0.2

1 km

N/A

Note: * assumes 30% uncertainty in the aerosol extinction-to-backscatter lidar ratio, Sa

 

If you are interested in taking part in this collaborative endeavor, please provide us with a brief letter of intent describing your proposed measurements, e-mail address and fax number. Guidelines for the CALIPSO collaborative measurements are as follows:

§         Measurements should be made as close as possible in time and space to the CALIPSO ground track.
§         Measurements made within 2 hours and 40 km are preferred.
§         Measurements made within 4 hours and 80 km are considered acceptable.
§         Measurements should be made to comparable (or better) accuracy and resolution as the CALIPSO measurements.

A data sharing protocol will be developed and supported at a no-exchange-of-funds basis. We will forward a copy of our validation plan to you when it is completed. We encourage you to collaborate with us on this very important atmospheric mission. For more information please check the CALIPSO quid pro quo validation website at www.calipsovalidation.hamptonu.edu. If you have any questions, please contact Dr. Thomas A. Kovacs of Hampton University, who will lead these validation activities. We look forward to hearing from you.

Sincerely,

Thomas A. Kovacs
Coordinator, QPQ Validation Program
tom.kovacs@hamptonu.edu

M. Patrick McCormick
Co-Principal Investigator : CALIPSO
pat.mccormick@hamptonu.edu

 

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