Comparison of Disdrometer and Rain Gauge Measurements during pre-CHUVA*
Ali Tokay1,2, Paul G. Bashor3,4, David B. Wolff5,2, Walter A. Petersen6, and Matthew Schwaller2
1JCET - University of Maryland Baltimore County 2NASA Goddard Space Flight Center 3Computer Sciences Cooperation 4NASA Wallops Flight Facility 5Science Systems Applications Inc. 6NASA Marshall Space Flight Center
*Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the globAl precipitation measurement
Field Campaign period: March 1-26, 2010 Pre-CHUVA Data Acquisition Network
-01.5
X-band polarimetric radar Disdrometer&Gauge site (INPE) Atlantic Disdrometer&Gauge site (Airport) -02.0 Ocean Maranhao Admirari State Anemometer tower Alcantara Sao Luiz International Airport
25 km University of Maranhao -02.5 50 km Sao Luiz 75 km (radar-airport) = 5.8 km 100 km (radar-INPE) = 2.0 km (radar-Admirari) = 7.7 km -03.0 (airport-INPE) = 4.3 km (airport-Admirari) = 2.4 km (INPE-Admirari) = 5.9 km
-03.5 -45.5 -45.0 -44.5 -44.0 -43.5 Longitude (degree) pre-CHUVA Disdrometer & Rain Gauge Sites
Parsivel disdrometer
TB Rain gauges Joss-Waldvogel disdrometer
Airport Site INPE Site Comparison of Rain Accumulation Comparison of Rain Accumulation Comparison of Rain Accumulation Comparison of Raindrop Size Distribution (event) Comparison of Raindrop Size Distribution (event) Comparison of Raindrop Size Distribution (event) Comparison of Raindrop Size Distribution (event) Comparison of Raindrop Size Distribution (instrument) Comparison of Raindrop Size Distribution (microphysics) OTT Parsivel Fall Velocity Measurements Parameterization of Raindrop Size Distribution
* D m D N(D) NTf(m)( ) exp[(4 m) ] Dmass Dmass
(4 m )m1 f(m ) * NT where NT (m 1) Dmass
D m D N(D) Nwg(m)( ) exp[(4 m) ] Dmass Dmass
4m 256W 6(4 m) N where g(m) w 4 256(m 4) wDmass Comparison of Raindrop Size Distribution Parameters
Gamma model parameters 03/20/10 03/21-22/10 03/24/10 03/24/10
* Normalized intercept (NT ) 113 155 77 134
Normalized intercept (Nw) 1486 2825 1090 1495
Mean mass Diameter (Dmass) 2.03 1.64 2.01 1.87 Shape parameter (m) 2.4, 1.7 4.2, 2.8 2.7, 2.8 1.8, 2.1
Gamma model parameters 03/20/10 03/21-22/10 03/24/10 03/24/10 * Normalized intercept (NT ) 106 135 68 82
Normalized intercept (Nw) 989 2151 447 1109
Mean mass Diameter (Dmass) 2.45 1.83 2.85 2.44 Shape parameter (m) 1.2, 0.4 3.3, 1.6 0.6, -0.6 2.5, 1.9 Comparison of Integral Rain Parameters
Integral rain parameters 03/20/10 03/21-22/10 03/24/10 03/24/10
Concentration (NT ) 231 255 155 250 Liquid Water Content (W) 0.314 0.253 0.219 0.225
Rain Rate (RR) 7.0 5.0 4.9 4.8
Reflectivity (Z) 39 35 37 36
Integral rain parameters 03/20/10 03/21-22/10 03/24/10 03/24/10
Concentration (NT ) 262 248 196 201 Liquid Water Content (W) 0.438 0.300 0.366 0.483
Rain Rate (RR) 10.6 6.3 9.3 11.9
Reflectivity (Z) 43 37 45 43 Comparison of Raindrop Size Distribution Parameters
200 1.0
0.5 100
0.0 0 -0.5 -100 -1.0
-200 -1.5 1355 specta 1355 specta -300 -2.0 -1 0 1 2 -1 0 1 2 10 10 10 10 10 10 10 10 Joss-Waldvogel Rain Rate (mm) Joss-Waldvogel Rain Rate (mm) Comparison of Integral Rain Parameters
10 10
5 5
0 0
-5 -5
-10 -10
-15 -15 1355 specta 1355 specta -20 -20 -1 0 1 2 -1 0 1 2 10 10 10 10 10 10 10 10 Joss-Waldvogel Rain Rate (mm) Joss-Waldvogel Rain Rate (mm) Probability and Cumulative Distributions of Raindrop Size Distribution Parameters
0.10 1.0 0.10 1.0 pd (JW) cd (JW) pd (Parsivel) cd (Parsivel) 0.08 0.8 0.08 0.8
0.06 0.6 0.06 0.6
0.04 0.4 0.04 0.4
0.02 0.2 0.02 0.2
0.00 0.0 0.00 0.0 1 2 3 0 1 2 3 4 10 10 10 Mass_weighted_diameter (D , mm) -3 mass Concentration (NT, m ) Probability and Cumulative Distributions of Integral Rain Parameters
0.10 1.0 0.10 1.0 pd (JW) cd (JW) pd (Parsivel) cd (Parsivel)
0.08 0.8 0.08 0.8
0.06 0.6 0.06 0.6
0.04 0.4 0.04 0.4
0.02 0.2 0.02 0.2
0.00 0.0 0.00 0.0 -1 0 1 2 0 2 4 6 10 10 10 10 10 10 10 10 6 -3 Rain rate (RR, mm hr-1) Reflectivity (Z, mm mm )