FMCW Cloud Radar

|| 특성

ㆍ 94GHz : X-band 및 K-band 보다 높은 Sensitivity

ㆍ -45DBz at 5km with 1.7s averaging time

ㆍ Solid State 송신기 사용 : Pulse 레이다에 비해 가격 저렴

ㆍ 해상도 1m 가능

ㆍ 최소관측거리 : 50m로 경계층 정밀관측 및 안개 관측 가능

ㆍ 강한 강수에도 수신기 satuaration 미 발생

ㆍ 모든 부품 열 차단 in-house 설치로 정확도 안정성 확보

ㆍ Low System Noise

ㆍ Transmitter aging 효과로 인한 송신기 신호 변화 제거

ㆍ 89GHz passive 채널 수신기 추가 탑재 : Liquid Water Path(LWP) 측정

ㆍ 레이다 수신기 및 Passive 수신기 NO2 켈리브레이션 : 질소 사용 절대온도 켈리비레이션으로 장기간 안정도 유지

ㆍ Dicke Switching 캘리브레이션 : 주기적인 단기간 켈리브레이션 수행

ㆍ Built-in Weather 센서 : 지상 기상 모니터링, Retrieval evaluation reference로 사용, 자료 분석에 활용.

ㆍ 소형으로 이동형 차량 탑재 관측

ㆍ Low Voltage 사용 : 습한 날씨에 discharge로 인한 장비오류 저하

|| Configurations


1. Verically pointed single polarization configuration (RPG-FMCW-94-sp)

Measured parameters
Moment data:Reflectivity, Mean radial velocity, Spectrum width, Skewness, Kurtosis
Spectral data:Reflectivity spectra



2. Scanning single polarization configuration

Measured parameters
Moment data:Reflectivity, Mean radial velocity, Spectrum width, Skewness, Kurtosis
Spectral data:Reflectivity spectra



3. Vertically pointed dual polarization configuration

Measured parameters
Moment data:Reflectivity, Mean radial velocity, Spectrum width, Skewness, Kurtosis
Integrated polarimetric data:Linear depolarization ratio(LDR), co-cross-channel correlation coefiicient ρcx
Spectral data:Reflectivity spectra
Spectral polarimetric data:sLDR, sρcx



4. Scanning dual polarization configuration

Measured parameters
Moment data:Reflectivity, Mean radial velocity, Spectrum width, Skewness, Kurtosis
Integrated polarimetric data:Differential reflectivity (ZDP), Cross-channel correlation coefficient ρhv, Differential phase
shift ΦDP, Differential attenuation ADR, Propagational differential phase shift KDP, Slanted Linear depolarization ratio (SLDR), co-cross-channel correlation coefficient in the slanted basis ρcx
Spectral data:Reflectivity spectra
Spectral polarimetric data:sZDR, sρhv, sΦDP, sSLDR, sρcx



5. Dual frequency configuration (K-band and W-band FMCW Radar)

The RPG W-band cloud radar can be complemented by a RPG Ka-band FMCW radar (35 GHz) that has a similar form factor and can be set up at the same scanning platform as the W-band radar. Having a combination of two frequencies such system will additionally provide measurements of the dual wavelength ratio. Due to different absorption by liquid water at Ka and W bands, the dual wavelength ratio can not only indicate a presence of supercooled liquid layers in mixed-phase clouds but also provides information about liquid water content. As the system also has the passive channel at 89 GHz the continuous consistency checks of measured liquid water content profiles with retrieved liquid water path can be performed. The dual wavelength configuration can also be employed for characterization of size and shape of particles producing non-Rayleigh scattering.
Note: the Ka-band radar can be also provided as a single instrument having the same configurational options as the W-band radar