A complete understanding of the Earth’s hydrologic cycle necessarily dictates an ability to accurately quantify the global range of precipitation rates and types (rain, snow etc.). In turn, global observations of precipitation are most efficiently made from space. Great strides in the measurement of global tropical rainfall have occurred recently as a result of the NASA Tropical Rainfall Measurement Mission (TRMM).

n all, 9 snowfall events were observed during IOP-3. All of these events were observed by the King City radars, 8 of the events were observed by the University of Massachusetts 3-frequency (W-, Ka, and Ku-band) Advanced Multi-Frequency Radar (AMFR), and 3 of the events were also observed with Convar-580 overflights.

This document is a case summary of the dates, times, snowfall types, and instruments used during these 9 IOP-3 snowfall events.

Parsivel Distrometer Results presented at the American Geophysical Union, Spring 2007.

A series of measurements at the CARE site from the 2DVD instrument.

Overview of the Parsivel instrument:

• Measures size and fall velocity of hydrometeors
• Present weather sensor
• Sampling area: ~50 cm2, varies with drop diameter
• Number of size and velocity bins: 32 x 32 matrix
• Drop size range: 0.06-24.5 mm
• Velocity range: 0.05-20.8 m/sec
• Operation period at Wallops Island: Spring 2002 - present
• Manufacturer: OTT in Germany www.ott-hydrometry.de