Analysis of ARM cirrus data and the incorporation of Doppler Fall-velocity measurements in lidar/radar retrievals Outline of lidar/radar procedure. Problem of habit and bi-modality. How Vd may help.

Active (lidar/radar) cloud remote sensing lidar Lidar Rada r Returned Power Time or Range LidarRadar Difference in returns is a function of particle size !!   nm  3-100mm

Effective size for ice crystals Ice particles are large compared to lid (Optical scattering regime) Ice particles are small compared to rad (Rayleigh scattering regime) Exact treatment of scattering difficult (impossible?) However: Confirmed using DDA and RT calculations

R' eff -vs-R eff for ice crystals Must know relationship between crystal Mass and maximum dimension (D) in order to predict R eff and IWC !

Lidar/Radar Inversion Procedure Lidar+Radar Signals  /Z e =F(R' eff ) Retrieve R' eff,  Habit/size dist form info. R eff IWC Radar Reflectivity Lidar Signal Effective Radius IWC Extinction

April 18, 1996, CLARA

CLARE’98 ARAT/C-130 flight INSU ARAT UKMO C-130 Leandre 532 nm lidar Kestral 94 Ghz Radar -- Good comparision between in-situ 2-D probe and airborne lidar/radar results ! (During CLARE'98) Good comparision between in-situ 2-D probe and airborne lidar/radar results ! (During CLARE'98) Good agreement with IR radiometer observations (During CLARA) Good agreement with IR radiometer observations (During CLARA) Donovan and van Lammeren and Donovan et al

C-130 2D vs Lidar/Radar results D-binned A-binned

Application to ARM data 35-GHz Radar, 532 nm Lidar Jan 14, range/time points !! 5 months Data Lidar signal Radar Z e R' eff IWC'=IWC(R' eff /R eff ) Complex polycrystals Hex-Plates

Comparision with Kristjansson (Mitchell) Function of Temperature only (based on Aircraft data from FIRE/CEPEX) Assume a crystal habit and convert to R'eff using their size-dist. model. Complex polycrystals Hex-Plates Overall pattern similar but large degree of variability at a given temperature How do things vary with IWC ?

Bin by IWC' (not yet IWC) IWC'=IWC (R'eff/Reff) Increasing IWC' g/m 3

Fit to simple bi-modal size distribution model (Must assume a crystal model !) ½ Maximum dimension Bi-Modal Size dist with fixed small mode Increasing N 2 Increasing r eff,2 Increasing N 2 Model Increasing IWC' Fit to Observations N2=F(IWC') r eff,2 =F(T) N2=F(IWC') r eff,2 =F(T)

Translate to R eff and IWC (use size-dist function and assume crystal habit) T=-35C IWC=0.01 g/cm 3 IWC=0.1 g/cm 3 Polycrystals Bullet Rosettes

R' eff -vs-R eff may be a problem. Depends on habit and effective varience of size-dist. Range of R' eff /R eff much small for a given habit if dist is effectivly "uni-modal". So less of an issue in clouds with a lot of "large-particles" Problem when only a few large particles exist.

R' eff -vs-R eff for "bi-modal" ice clouds Sample distributions R' eff /R eff as function of N 2 /N 1 and R' eff

How may V d help ? Fall speed depends on Mass and Area of particles. Measurement of Ze weighted V d has some size information embedded.

Doppler vel -vs- R'eff Function of Habit and degree of bi-modality ! Curves from bi-modal size-dist model N 2 /N 1 =5x10 -3 N 2 /N 1 = 5x10 -8 N 2 /N 1 > 0.05

Summary Results of analysis of 5 months ARM data published in GRL (no doppler) CLARE'98 data anaylsed in similar fashion. Will continue to investigate Vd-R'eff relationship.

ARAT Lidar/Radar Results Oct,

Future Tasks/Plans/Ideas Test radiative property parameterization in RTM. Use inversion products in radiative transfer schemes and compare with surface obs. Incorporate Doppler fall-speed info into retrieval procedure. Extend lidar/radar procedure to space-based lidar/radar instruments (CloudSat/Calipso, EarthCARE). Development of more advanced retrival schemes incorporating passive sensor information.

Types of Equivalent spheres Same opt. extinction Same Ze Same Ze and alpha ?

Comparisions (size dists. of plates)

Comparisions (size dists. of Columns)

Backscatter still varies though ! Plates Columns

Experimental Activities Centered at CABAW (center of Netherlands) Other stations have celiometers and SW flux measurements (some also with IR radiometers) Cabaw + Network useful for CSAT/CALYPSO Validation ? Active in: CloudNET/BBC/CliwaNet

Validation Two JGR-Atmosphere papers (In Press) Good agreement with IR radiometer observations (During CLARA) Good agreement with IR radiometer observations (During CLARA) Good comparision between in-situ 2-D probe and airborne lidar/radar results ! (During CLARE'98) Good comparision between in-situ 2-D probe and airborne lidar/radar results ! (During CLARE'98) UKMO C-130 INSU ARAT Leandre 532 nm lidar Kestral 94 Ghz Radar INSU ARAT

CABAW 200 meter met. tower + expanding number of ground-based remote sensing equipment