Year-end Sale % OFF 
Abstract
A new dual-frequency Doppler polarimetric cloud radar (DDCR), working at 35-GHz (Ka-band radar, wavelength: 8.6 mm) and 94-GHz (W-band radar, wavelength: 3.2 mm) frequencies, has been in operation at Yangbajing Observatory on the Tibetan Plateau (China) for more than a year at the time of writing. Calculations and field observations show that the DDCR has a high detection sensitivity of −39.2 dBZ at 10 km and −33 dBZ at 10 km for the 94-GHz radar and 35-GHz radar, respectively. The radar reflectivity measured by the two radars illustrates different characteristics for different types of cloud: for precipitation, the attenuation caused by liquid cloud droplets is obviously more serious for the 94-GHz radar than the 35-GHz radar (the difference reaches 40 dB in some cases), and the 94-GHz radar lost signals due to serious attenuation by heavy rainfall; while for clouds dominated by ice crystals where the attenuation significantly weakens, the 94-GHz radar shows better detection ability than the 35-GHz radar. Observations in the Tibetan region show that the 35-GHz radar is prone to missing cloud near the edge, such as the cloud-top portion, resulting in underestimation of the cloud-top height (CTH). Statistical analysis based on one year of observations shows that the mean CTH measured by the 94-GHz radar in the Tibetan region is approximately 600 m higher than that measured by the 35-GHz radar. The analysis in this paper shows that the DDCR, with its dual-frequency design, provides more valuable information than simpler configurations, and will therefore play an important role in improving our understanding of clouds and precipitation in the Tibetan region.
Highlights
Water on the Earth’s surface receives solar radiation, and evaporates to water vapor that is brought to higher levels by vertical movements such as convection, turbulence, orographic uplift, and so on
In February 2014, the core observation platform, GPMCO (GPM Core Observatory), of the global precipitation measurement plan, GPM (Global Precipitation Measurement), was launched, equipped with the world’s first dual-frequency satellite radar (Ku-13.6 GHz, Ka-35.5 GHz), in order to replace the TRMM (Tropical Rainfall Measuring Mission) satellite that had been in service for an extended period of time to detect the structure of cloud precipitation on a global scale
The dual-frequency millimeter-wavelength radar introduced in this paper is the first dual-frequency millimeter-wavelength radar developed in China for long-term observation of clouds and precipitation over the Tibetan
Summary
Water on the Earth’s surface receives solar radiation, and evaporates to water vapor that is brought to higher levels by vertical movements such as convection, turbulence, orographic uplift, and so on. The Atmospheric Radiation Measurement Program (ARM), supported by the U.S Department of Energy, has used multiple-frequency radars, including millimeter-wavelength radars, to carry out observations of cloud and precipitation at many ARM sites [19]. In February 2014, the core observation platform, GPMCO (GPM Core Observatory), of the global precipitation measurement plan, GPM (Global Precipitation Measurement), was launched, equipped with the world’s first dual-frequency satellite radar (Ku-13.6 GHz, Ka-35.5 GHz), in order to replace the TRMM (Tropical Rainfall Measuring Mission) satellite that had been in service for an extended period of time to detect the structure of cloud precipitation on a global scale (https://gpm.nasa.gov/, accessed on 17 November 2021). The dual-frequency millimeter-wavelength radar introduced in this paper is the first dual-frequency millimeter-wavelength radar developed in China for long-term observation of clouds and precipitation over the Tibetan.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
