NASA - National Aeronautics and Space Administration

Estimation of surface wind speed by matching the shape of the reflected GPS signal correlation function against analytical models. Wind speed obtained from this method has agreed with that recorded from buoys with a bias of less than 0.1 m/s, and with a standard deviation of 1.3 m/s.

A modified GPS receiver is used to track the direct line of sight satellites through a zenith-oriented right hand circularly polarized (RHCP) antenna and record the cross-correlation function of the reflected signals using a nadir-oriented left hand circularly polarized (LHCP) antenna. The cross-correlation for one or two satellites is continuously recorded in 10 to 12 range bins. Accumulation is done in hardware for an integration time of 1 ms. Batches of 0.1 seconds of the sum square of the inphase and quadrature components are then averaged before being saved to disk.

WISE is an airborne sounder designed to measure the nadir ice thickness of warmer and fractured glacier. Its design is based on a successful planetary sounder MARSIS that enables scientist to discover layered water-ice deposits near Mars poles.

The airborne sounder uses 15-300 meter long wavelengths in order to penetrate into rough surfaces, voids, and cracks before they are reflected by the interface between ice and bedrock. This makes the system well suited for the study of outlet glaciers whose internal structures are very complicated due to fast-moving surfaces and proximity to a relatively warm body of ocean.

Such an investigation will provide us with valuable information such as ice stratigraphy and the ground slope of the bedrock layer as well as ice thickness, which is very important to construct a reliable ice-flow model.

The High Altitude Monolithic Microwave integrated Circuit (MMIC) Sounding Radiometer (HAMSR) is a microwave atmospheric sounder developed by JPL under the NASA Instrument Incubator Program. Operating with 25 spectral channels in 3 bands (50-60 Ghz, 118 Ghz, 183 Ghz), it provides measurements that can be used to infer the 3-D distribution of temperature, water vapor, and cloud liquid water in the atmosphere, even in the presence of clouds. The new UAV-HAMSR with 183GHz LNA receiver reduces noise to less than a 0.1K level improving observations of small-scale water vapor. HAMSR is mounted in payload zone 3 near the nose of the Global Hawk.

HAMSR was designed and built at the Jet Propulsion Laboratory under the NASA Instrument Incubator Program and uses advanced technology to achieve excellent performance in a small package. It was first deployed in the field in the 2001 Fourth Convection and Moisture Experiment (CAMEX-4) - a hurricane field campaign organized jointly by NASA and the Hurricane Research Division (HRD) of NOAA in Florida. HAMSR also participated in the Tropical Cloud Systems and Processes (TCSP) hurricane field campaign in Costa Rica in 2005. In both campaigns HAMSR flew as a payload on the NASA high-altitude ER-2 aircraft. It was also one of the payloads in the 2006 NASA African Monsoon Multidisciplinary Activities (NAMMA) field campaign in Cape Verde - this time using the NASA DC-8. HAMSR provides observations similar to those obtained with microwave sounders currently operating on NASA, NOAA and ESA spacecraft, and this offers an opportunity for valuable comparative analyses.

MOPITT (Measurements Of Pollution In The Troposphere) is a carbon monoxide and methane remote sounder launched in 1999 with the Terra spacecraft. An aircraft replica (MOPITT-A) was developed at the University of Toronto to perform validation of MOPITT radiances as well as small-scale pollution studies. MOPITT-A is based on the engineering model of MOPITT, modified for flight in NASA's ER-2 research aircraft. The instrument was first tested over California from the NASA Dryden Flight Research Center in July 2000.

In 1991, NASA initiated an airborne remote sensing program in conjunction with coordinated surface measurements for determining the mass balance of the Greenland ice sheet, which plays in important role in the rise of global sea level. Starting in 1995, NASA combined various efforts on the mass-balance studies into a coordinated effort called Program in Arctic Regional Climate Assessment (PARCA). The University of Kansas has been participating in this program to make airborne ice thickness measurements using coherent radar depth sounders. Since 1993, the authors have collected a large volume of ice-thickness data over the ice sheet. They have demonstrated that coherent radars can acquire ice thickness and internal structure data over the thickest part of the ice sheet and outlet glaciers located around the ice margin.