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NPOL: GPM Precipitation Science Research Facility

NASA/GPM Radar Assets


NASA S-Band Dual-Polarimetric Radar (NPOL)

NPOL is NASA's premier weather radar. It is one of only two mobile S-band dual-polarization radars (the other being NCAR's SPOL). When not being deployed for PMM/GPM field campaigns, it is operated near NASA's Wallops Flight Facility in Newark, MD.

NPOL has a wavelength of 10.65 cm, an operating frequency of 2700-2900 MHz, variable PRF of 500 and 1000 Hz with a 0.95 degree beam width. NPOL can operate with both horizontal and vertical polarization in both simultaneous and alternating modes. The radar has a prime-focus parabolic reflector which is 8.5 m in diameter and is housed on five sea-tainers. When readied for deployment, the entire radar and antenna system is stored within the five seatainers.

The image to the right shows a network of rain gauges and disdrometer deployed in the NPOL domain. All of these instruments are being used to help validate GPM satellite over an area of 0.5 degrees latitude x 0.5 degrees latitude. Click on on the image to see a higher resolution map of the network.

BirdBath Scan [Zdr cal]

Enlarge Birdbath

Animated GIF

Relative Calibration Adjustment

Latest Daily RCA Values

Latest Hourly RCA Values


More RCA info:

Pointing Accuracy

The pointing accuracy of the NPOL antenna is monitored by analyzing daily SunCal scans. These plots are generally run twice daily, once in the morning and the other in later afternoon, which provides additional detail on the level of the dish.

The plots to the right show the time series of estimated pointing error, as determined by the SIGMET SolarCal utility for Azimuth (top) and Elevation (bottom). Click on the image to see an expanded image. The blue triangles represent the AM scans, while the red triangles represent the PM scans. Ideally, these would be centered +/- some delta around zero, so an offset indicates a possible actual pointing issue.

More SunCal info

Absolute Calibration

Absolute Calibration: GPM uses both Self-consistency and comparisons between disdrometers and the radar to provide estimates of the absolute calibration. Click here to see the frequently updated NPOL Bias Table.

Latest NPOL PPI Imagery

Current Sounding: Current Sounding: 11/17/2017 @ 23 UTC.

Reflectivity

Velocity

Differential Reflectivity

Rain Rate

Correlation

Intercept (Nw)

Mass-Weighted Diameter

Hydrometer ID

Latest NPOL RHI Imagery

Current Sounding: Current Sounding: 11/17/2017 @ 23 UTC.

Reflectivity

Velocity

Diff. Reflectivity

Rain Rate

Correlation

Intercept (Nw)

Mass-Weighted Diameter

Hydrometer ID

Click each image to zoom

Notes on the Hydrometeor Identfication Images

The HID product is generated using software provided by Colorado State University and is based on the continued work of Dolan et al. (2013). The classifications are:
UC Unclassified
DZ Drizzle
RN Rain
CR Ice Crystals
DS Dry Snow
WS Wet Snow
VI Vertically-aligned Ice
LDG Low-density Graupel
HDG High-density Graupel
HA Hail
BD Big Drops

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