ESA-JAXA Pre-Launch EarthCARE
Science and Validation Workshop
13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Validation Plan for EarthCARE/CPR Using Scanning Ka-Band Cloud Radar
Tadayasu Ohigashi1 and Ryohei Misumi2
1:NIED (National Research Institute for Earth Science and Disaster Resilience),
Tsukuba, Japan
2:Nihon University, Tokyo, Japan
JAXA AOID 7: EarthCARE validation dataset created using ground based
Ka-band radar and microwave radiometer observations

Overview of validation plan
We are planning validation of the EarthCARE, mainly
CPR (W-band (94 GHz) radar), using the ground-based
Ka-band (35 GHz) radars and microwave radiometers(MWR) of the National Research Institute for Earth
Science and Disaster Resilience (NIED).

1. statistical (climatological) comparison
Since the frequency of observation of the same point(area) of EarthCARE is small, we plan to create a data
set for statistical (climatological) comparison.
2. direct(simultaneousandsamelocation)comparison
Using scanning capability of the cloud radars,
simultaneous and same location comparison are alsoplanned.
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

TokyoStatistical comparison(climatological comparison using CFAD)

CloudSat©NASA•••••

Five cases (Aug.-Oct. 2017)
Around Kanto

Ka-band Radar

Z (vertical obs., Z>-13dBZ)

1 month (Oct. 2019)
Ka1 (Tsukuba)
90°-PPI every 3 minutes

Doppler velocity(vertical obs., Z>-13 dBZ）

ZDR(RHI, Z>-9dB）• CloudSat (EarthCARE) samples are small and will beneeded more samples (extension of range andperiod).
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Statistical comparison(case study using CFAD, quasi-simultaneous comparison)
Day:255 2017/09/12

Day:287 2017/10/14

CloudSat

CloudSat©NASAKa-band Radar

Ka-band Radar• Roughly speaking, CloudSat’s and Ka-band radars’ Z agree well, in the upper levels.
• At Z>～10 dBZ, differences are large. This may be the same reason as point-by-point comparison (non-Rayleighscattering of CloudSat W-band radar).
• InPre-Launch
the lowestlevels,
attenuation
may| 13cause
some2023
differences.
ESA-JAXA
EarthCARE
Science andValidation Workshop– 17 November| ESA-ESRIN, Frascati (Rome), Italy

LWP of MWR
LWC estimated using MWR and Ka-band radar
Comparison of LWP

Comparison of LWC using MWR LWP
In-situ(Skytree tower)© JAXA

Satellite AMSR2Ground-based MWR
Ka & MWR• Ground-based MWR liquid water path
(LWP) is reasonable for a certain range• We are developing estimation-2(10-1000 g m ) when compared tomethod of LWC, using MWR
satellite.
LWPandKa-bandradarreflectivity.
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Point-by-point comparison(simultaneous, same point)• Roughly speaking, CloudSat’s andKa-band radars’ Z agree well.
• At Z> ～ 10 dBZ, differences arelarge. This may be due to nonRayleigh scattering of CloudSat
W-band radar.

©NASAESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Comparison using vertical cross section
created from a CAPPI of Ka-band radar
Number ofelevation angles

CAPPI at 5050 m©NASA•Scans with a sufficiently number of elevation
angles will be required for comparison.

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Summary of comparison methods between
EarthCARE and ground-based observations
Methodstatistical

DetailAdvantages and disadvantages＋Can be compared even in different
climatologicalyears.
histogram/CFAD/CFTD－Need enough satellite samples.
＋Almost no time lag.
case study－Larger errors in spatially non-uniform
histogram/CFAD/CFTD
clouds.
point-by-pointdirect(only Z)

cross section of CAPPI＋Almost no time and space lag.
－Few chances.
＋Almost no time and space lag.
－Few chances. Coarse verticalresolution.

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy