Algorithm to pick out ground

Mean counts, binned by range, Feb-April 2011 (ground removed)

Normalized range counts by precipitation periods (ground removed)

Mean counts binned by height, Feb-April 2011 (ground removed)

Normalized height counts by precipitation periods

January 20-23, 2012

February 12-16, 2012

The slope coefficient for the regression, 1.7e-5

cm/count,is an order of magnitude smaller than the slope

coefficient from theJanuary storm, 2.3e-04

cm/count

Slope coefficient summarycounts/cm (hourly scans) Time period

5.1e-5 Feb-April 2011

1.7e-5 Jan 20th-23rd (biggest storm of season)

2.3e-4 Feb 12-16th (inside slider, cold)

• Elaborating Ned's SOW:

• NEXT THREE MONTHS

• Literature review (NED w/ awareness/cognition Bert & Jeff): 2-6 WEEKS• What goes on with LiDAR in use already? (PD, ARO, NSF, ERDC)

– Principle of operation of different types in use (e.g., polarization, intensity, do they count individual events?)– Do any count number densities of particles directly? Indirectly?

• What factors affect the size of snowflakes below clouds (e.g., intervening layers in the atmosphere, wind speed, humidity, temperature)? (PD, ARO, NSF, ERDC)

• What does precipitation radar do (e.g., principle of operation)? (PD, ARO, NSF, ERDC) – Why does snowfall give radars problems?– Do radars offer a decent measure of mass of precipitation?

• What state of the art do we see in measuring snowfall? (PD, ARO, NSF, ERDC) – Different collectors and the collection efficiency problem– What do we consider actual precipitation (e.g., SWE on the ground)?– What other approaches exist to characterize snow particles in the air (e.g., drift meters)?

• BIG QUESTIONS (NSF) – How much uncertainty exists in the mass balance of the great ice sheets (e.g., Greenland, Antarctica)?– How do we estimate precipitation?– How do we estimate sublimation?– Do we account for drift-induced sublimation? How?

• Data processing (Ned & Jeff)• Learn to export x,y,z, intensity, time (Ned)• Correlate raw counts in a volume, accumulated over several scans, with snow height accretion (Ned)

– Do with data having atmosphere as background– Do with data having reflectors as a background

• Evaluate the scatter in the scattergrams v. wind speed, etc. (Ned)• Begin to formulate sampling theory for a diverging beam (Ned & Jeff)• Formulate a hypothesis about what a count means (Jeff & Ned)