**The Jetstream 31 (J31) in INTEX-B/MILAGRO:\
Science Goals, Instrument Payload, and Plans\
\
**Lead PI: Phil Russell, NASA Ames Research Center

Instrument PIs:

Jens Redemann, NASA Ames and Bay Area Environmental Research Institute

Peter Pilewskie, University of Colorado

Brian Cairns, Columbia University

Charles Gatebe and Michael King, NASA Goddard Space Flight Center

Rose Dominguez, NASA Ames University-Affiliated Research Center

Warren Gore, NASA Ames Research Center

In INTEX-B/MILAGRO the Jetstream 31 (J31) will focus on measuring the
properties and radiative effects of aerosols, water vapor, clouds and
surfaces, as a means of better understanding their impacts on climate
and advancing spaceborne and airborne measurement science. Specific
goals of the J31 are to:

● Characterize the distributions, properties, and effects of aerosols
and water vapor advecting from Mexico City and biomass fires toward and
over the Gulf of Mexico, including

-   Aerosol optical depth and extinction spectra (354-2138 nm)

-   Water vapor columns and profiles

-   Aerosol radiative impacts: in clear sky (direct effect) and via
    clouds (indirect effect)

● Test the ability of Aura, other A-Train and Terra sensors, and
airborne lidar to retrieve aerosol, cloud, and water vapor properties

● Characterize surface spectral albedo and bidirectional reflectance
distribution function (BRDF) to help improve satellite retrievals

● Quantify the relationships between the above and aerosol amount and
type

![](media/image1.jpeg){width="4.875in" height="1.8243055555555556in"}

+------------------------------------+---------------------------------+
| Length                             | 47' 2"                          |
+------------------------------------+---------------------------------+
| Wingspan                           | 52'                             |
+------------------------------------+---------------------------------+
| Ceiling                            | 25,000'                         |
+------------------------------------+---------------------------------+
| Airspeed                           | 220 kt                          |
|                                    |                                 |
| Max cruise @ 16,000'               | 150 kt                          |
|                                    |                                 |
| Survey                             |                                 |
+------------------------------------+---------------------------------+
| Range                              | 850 nmi                         |
+------------------------------------+---------------------------------+
| Endurance                          | 5 hr (incl 1 hr reserve)        |
+------------------------------------+---------------------------------+

To address the above goals the J31 will carry a payload of the following
six instruments:

● Ames Airborne Tracking Sunphotometer (AATS-14), PI Jens Redemann

● Solar Spectral Flux Radiometer (SSFR), PI Peter Pilewskie

● Research Scanning Polarimeter (RSP), PI Brian Cairns

● Cloud Absorption Radiometer (CAR), PIs Charles Gatebe and Michael King

● Position and Orientation System (POS), PI Rose Dominguez

● Meteorological Sensors and Nav/Met Data System (NavMet), PI Warren
Gore

Each of the first four instruments (AATS, SSFR, RSP, CAR) has specific
science objectives, including objectives that combine data from several
J31 instruments. Each instrument and its objectives are described in an
accompanying 1- to 2-page writeup.

The above J31 science goals and the instrument-specific objectives
require the J31 flight patterns illustrated below.

![](media/image2.png){width="4.375in" height="2.701388888888889in"}

\(1\) Survey Vertical Profile. (2) Minimum-Altitude Transect. (3)
Parking Garage (Stepped Profile). (3\') Parking Garage with CAR Orbits.
(4) Above-Cloud Transect. (4\') Above-Cloud CAR Orbit.

AATS, SSFR, POS, and NavMet flew on the J31 in INTEX-A in 2004. AATS,
POS, NavMet, and RSP flew on the J31 in ALIVE in 2005. The flight
patterns shown above include only small changes to those flown
successfully in INTEX-A in 2004.