Tag: yong-keun lee

TROPICS TMS observations of Hurricane Ida on 28 August 2021 at 20:07 UTC. TMS F-band and 205 GHz observations resolve finer hurricane structure in terms of eye, eyewall, and rainbands.

Evaluating Rainfall and Graupel Retrieval Performance of the NASA TROPICS Pathfinder Through the NOAA MiRS System

January 2, 2025

ESSIC scientists involved with the NASA TROPICS CubeSat mission recently built an algorithm for hydrometers retrieval. In a paper in Remote Sensing of Environment, John

Figure 1. Time series of global monthly anomalies of 2-meter air temperature (top) and TPW (bottom) derived from ERA5 analyses. The straight lines are the linear trends derived from the monthly anomalies. Anomalies and trends are shown for global means based on 1:30 am/1:30 pm local time data only (red) and all hourly data (black). The anomalies and trends for both data sets are so similar that the black curves are almost obscured by the red curves. Computed annual trend values for both 24-hour and 1:30 am/pm data are shown in blue and red, respectively.

Trends in Temperature, Water Vapor and Surface Pressure: Signals of Climate Change and Atmospheric CO2 Increases

December 10, 2024

ESSIC/CISESS scientists Yan Zhou, Chris Grassotti, Yong-Keun Lee, and John Xun Yang are co-authors on a new paper in Scientific Reports titled “Trends of temperature

Figure 3. Monthly TPW anomaly time series shown in red for ERA5 and blue for MiRS SNPP, 2012-2021. The straight lines are the linear regression fits. [a] is for global, [b] for Tropics, and [c] for mid-latitude regions, respectively.

Evaluation of Total Precipitable Water Trends From Reprocessed MiRS SNPP ATMS Observations

November 15, 2024

Figure 3. Monthly TPW anomaly time series shown in red for ERA5 and blue for MiRS SNPP, 2012-2021. The straight lines are the linear regression

Machine Learning-Based Estimation of Tropical Cyclone Intensity from Advanced Technology Microwave Sounder Using a U-Net Algorithm

February 20, 2024

ESSIC/CISESS scientists Yong-Keun Lee and Christopher Grassotti are co-authors on a new paper in Remote Sensing led by first author Zichao Liang, a student who interned with the MiRS team during the summer of 2023. NOAA scientists Lin Lin and Quanhua Liu also co-authored the paper. The paper, titled “Machine Learning-Based Estimation of Tropical Cyclone Intensity from Advanced Technology Microwave Sounder Using a U-Net Algorithm”, assesses the use of the U-Net model to estimate surface wind speed and surface pressure over pure ocean conditions.

Figure 1. The local perturbations in observed microwave brightness temperatures from an ascending orbit of (a) MetOp-B AMSU-A channel 14, (b) MetOp-C AMSU-A channel 14, a descending orbit of (c) NOAA-20 ATMS channel 15, and (d) SNPP ATMS channel 15 on January 15, 2022. The black triangle at the center for each panel is the Tonga volcano location. The outermost black-curved lines from the Tonga volcano location correspond to a phase speed of 330 m/s assuming that the perturbation has been generated at the time and location of initial volcanic eruption. From the 2nd outermost black-curved lines to the innermost lines, the phase speeds are 300, 270, and 230 m/s, respectively. The time information in each panel indicates the approximate observation time for the Lamb wave (between 300 m/s and 330 m/s indicated by black right-pointing triangles) and for the lead gravity wave (between 230 m/s and 270 m/s indicated by red right-pointing triangles). Red dots indicate the pixels where the brightness temperature perturbation is larger than 1.2 K.

Satellite Microwave Observations of the Hunga Tonga Eruption’s Atmospheric Waves

December 20, 2023

ESSIC/CISESS scientists Yong-Keun Lee and Christopher Grassotti are authors on a new paper in Geophysical Research Letters describing the first attempt to perform a detailed analysis of the stratospheric impact of the eruption from satellite microwave observations. The other authors on the paper are Neil Hindley from University of Bath and Quanhua (Mark) Liu from NOAA’s Center for Satellite Applications and Research.

Fig 1. The retrieved total precipitable water (TPW) and temperature (500 mb) from TROPICs are in good agreement with ECMWF analysis.

Atmospheric Sounding from the CubeSat TROPICS Mission

February 13, 2023

ESSIC/CISESS scientists John Xun Yang, Yong-Keun Lee, and Christopher Grassotti are co-authors on a new paper titled “Atmospheric humidity and temperature sounding from the CubeSat TROPICS mission: Early performance evaluation with MiRS” in Remote Sensing of Environment.

Fog over mountain tops, courtesy of NOAA

Using Satellite Microwave Data for Water Vapor Over Land

February 26, 2021

CISESS scientists Chris Grassotti and Yong-Keun Lee were coauthors of a paper published last week in the open access journal Remote Sensing.