Kun Zhang

Dr. Kun Zhang

Global Science & Technology, Inc.
orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 November 2018 in Journal of Cellular and Molecular Medicine
Verified
Journal Article
Open access
PDF file
JFJie Fan
Jie Fan
KZKun Zhang
Kun Zhang
YJYang Jin
Yang Jin
BLBingjin Li
Bingjin Li
SGShuohui Gao
Shuohui Gao
RCRan-Ji Cui
Ran-Ji Cui
Berberine, a natural isoquinoline alkaloid, is used in herbal medicine and has recently been shown to have efficacy in the treatment of mood disorders. Furthermore, berberine modulates neurotransmitters and their receptor systems within the central nervous system. However, the detailed mechanisms of its action remain unclear. This review summarizes the pharmacological effects of berberine on mood disorders. Therefore, it may be helpful for potential application in the treatment of mood disorders.

11 October 2021 in IEEE Transactions on Geoscience and Remote Sensing
Verified
Journal Article
Closed access
FIFlavio Iturbide-Sanchez
Flavio Iturbide-Sanchez
LSLarrabee Strow
Larrabee Strow
DTDavid Tobin
David Tobin
Yong ChenYong Chen
Yong Chen
DTDenis Tremblay
Denis Tremblay
HRHenry Revercomb
Henry Revercomb
The Suomi National Polar-orbiting Partnership (SNPP) cross-track infrared sounder (CrIS) has provided critical observations for environmental applications for nearly ten years. However, on 26 March 2019, the Joint Polar Satellite System (JPSS) interface data processing segment (IDPS) stopped producing the operational SNPP CrIS sensor data record (SDR) product due to a failure of the midwave infrared (MWIR) band. Following a comprehensive risk assessment, the switch from primary Side-1 to redundant Side-2 electronics was made on 24 June 2019, successfully recovering the full capabilities of the sensor. Comprehensive assessment results demonstrate the high quality of the CrIS SDR product resulting from the sensor recalibration, thus meeting the JPSS Level-1 requirements with margin. The spectral calibration prioritized consistency with the CrIS SDR product prior to the side switch to minimize the impact on users. The results show that the radiometric impact on the CrIS SDR product resulting from the side switch is not significant and is within the calibration radiometric uncertainty. It is demonstrated that after instrument restoration, the SNPP CrIS SDR product recovers the quality needed to be used as radiometric reference for calibration and validation of infrared remote sensing instruments. The recovery of the SNPP CrIS MWIR band is expected to support improvements in numerical weather forecasting by restoring the MWIR band channels sensitive to tropospheric water vapor. This should also help maintain continuity and redundancy of one of the backbone observations of the global observing system.

19 November 2018 in Journal of Geophysical Research: Atmospheres
Verified
Journal Article
Open access
PDF file
KZKun Zhang
Kun Zhang
AGAlbin J. Gasiewski
Albin J. Gasiewski
A numerical precision assessment and simulation results of the Unified Microwave Radiative Transfer (UMRT) model incorporating aspherical frozen hydrometeors based on the NASA Goddard Space Flight Center (NASA/GSFC) OpenSSP database are presented. It is shown that UMRT maintains unconditional numerical stability and computational efficiency for absorbing and scattering clouds. UMRT requires symmetry of the transition matrix for the discretized planar‐stratified radiative transfer equation to realize numerically stable and accurate matrix operations as required by the discrete ordinate eigenanalysis method. UMRT has heretofore been restricted to spherical polydispersive hydrometeors. In this study, the necessary block‐diagonal structure of the full Stokes matrix for randomly oriented OpenSSP aspherical hydrometeors is shown to be maintained, albeit with small asymmetric deviations, which introduce small asymmetric components into the transition matrix that are negligible for most remote sensing applications. An upper bound of the brightness temperature error calculated by neglecting the asymmetric components of the transition matrix under even extreme atmospheric conditions is shown to be small. Hence, the OpenSSP hydrometeor database can be reliably used within the UMRT model. Block‐diagonal Stokes matrix elements along with other single‐scattering hydrometeor parameters were subsequently used in radiative simulations of multistream dual‐polarization radiances for a simulated hurricane event to demonstrate the inherent numerical stability and utility of the enhanced UMRT model. An intercomparison of computed upwelling radiances for a multiphase distribution of aspherical OpenSSP hydrometeors versus a mass‐equivalent Mie hydrometeor polydispersion for key sensing frequencies from 10 to 874 GHz shows the considerable impact of complex (vs. simple spherical) hydrometeors on predicted microwave radiances.

5 August 2021 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Banghua YanBanghua Yan
Banghua Yan
MGMitch Goldberg
Mitch Goldberg
XJXin Jin
Xin Jin
DLDing Liang
Ding Liang
JHJingfeng Huang
Jingfeng Huang
KZKun Zhang
Kun Zhang
Two existing double-difference (DD) methods, using either a 3rdSensor or Radiative Transfer Modeling (RTM) as a transfer, are applicable primarily for limited regions and channels, and, thus critical in capturing inter-sensor calibration radiometric bias features. A supplementary method is also desirable for estimating inter-sensor calibration biases at the window and lower sounding channels where the DD methods have non-negligible errors. In this study, using the Suomi National Polar-orbiting Partnership (SNPP) and Joint Polar Satellite System (JPSS)-1 (alias NOAA-20) as an example, we present a new inter-sensor bias statistical method by calculating 32-day averaged differences (32D-AD) of radiometric measurements between the same instrument onboard two satellites. In the new method, a quality control (QC) scheme using one-sigma (for radiance difference), or two-sigma (for radiance) thresholds are established to remove outliers that are significantly affected by diurnal biases within the 32-day temporal coverage. The performance of the method is assessed by applying it to estimate inter-sensor calibration radiometric biases for four instruments onboard SNPP and NOAA-20, i.e., Advanced Technology Microwave Sounder (ATMS), Cross-track Infrared Sounder (CrIS), Nadir Profiler (NP) within the Ozone Mapping and Profiler Suite (OMPS), and Visible Infrared Imaging Radiometer Suite (VIIRS). Our analyses indicate that the globally-averaged inter-sensor differences using the 32D-AD method agree with those using the existing DD methods for available channels, with margins partially due to remaining diurnal errors. In addition, the new method shows its capability in assessing zonal mean features of inter-sensor calibration biases at upper sounding channels. It also detects the solar intrusion anomaly occurring on NOAA-20 OMPS NP at wavelengths below 300 nm over the Northern Hemisphere. Currently, the new method is being operationally adopted to monitor the long-term trends of (globally-averaged) inter-sensor calibration radiometric biases at all channels for the above sensors in the Integrated Calibration/Validation System (ICVS). It is valuable in demonstrating the quality consistencies of the SDR data at the four instruments between SNPP and NOAA-20 in long-term statistics. The methodology is also applicable for other POES cross-sensor calibration bias assessments with minor changes.

12 February 2022 in Remote Sensing
Verified
Journal Article
Open access
PDF file
ZWZhipeng Wang
Zhipeng Wang
FIFlavio Iturbide-Sanchez
Flavio Iturbide-Sanchez
PBPeter James Beierle
Peter James Beierle
KZKun Zhang
Kun Zhang
DTDenis Tremblay
Denis Tremblay
Radiometric intercomparison between satellite remote sensing instruments has become an increasingly common practice to monitor the stability and even the accuracy of their radiance products. The assessment also enables the evaluation of calibration improvements made to these products, as well as the identification and resolution of remaining calibration inadequacies. In this paper, the radiance products of the Cross-track Infrared Sounder (CrIS), an interferometer-based hyperspectral IR sounder in low Earth orbit (LEO), is compared with the level-1b (L1b) radiance products of the infrared (IR) bands of the Advanced Baseline Imager (ABI), an imaging radiometer in geostationary (GEO) orbit. Two CrIS instruments are currently in operation on S-NPP and NOAA-20 satellites, respectively, and two ABI instruments are in operation on GOES-16 and GOES-17 satellites, respectively. Radiometric intercomparisons are performed between each CrIS-ABI pair. An established procedure by GSICS for such GEO-LEO instrument comparison is principally followed to emulate the radiance of ABI IR bands from CrIS spectra of the collocated pixels to be compared with the actual ABI radiance. Results show that the long-term time series of CrIS-ABI radiance bias have been stable within 0.2 K for nearly all ABI IR bands within a spectral range from 3.7 μm to 13.3 μm, except those with known calibration issues. Miscellaneous calibration events that had occurred to either instrument and altered the biases are identified and explained. While the main goal of the work is to support the on-orbit Cal/Val of CrIS, including the future JPSS-2/3/4 CrIS, such observations can also be referenced to further improve the calibration of ABI.

23 March 2020 in IEEE Transactions on Geoscience and Remote Sensing
Verified
Journal Article
Closed access
KZKun Zhang
Kun Zhang
AGAlbin J. Gasiewski
Albin J. Gasiewski
A horizontally inhomogeneous unified microwave radiative transfer (HI-UMRT) model is presented to study the 3-D effects of the horizontal inhomogeneous clouds on the computed microwave radiances and facilitate satellite radiance assimilation over the horizontally inhomogeneous all-weather conditions. HI-UMRT provides a coupled two-Stokes parameter numerical radiance solution of the 3-D radiative transfer (RT) equation by embedding the existing 1-D UMRT algorithm into an iterative perturbation scheme. The horizontal derivatives in the radiances of the lower perturbation order are treated as the source functions of the azimuthal harmonic perturbation RT equations that are readily solved using the planar-stratified 1-D UMRT algorithm. The horizontal radiance derivative is estimated by central differencing. A perturbation source-function analysis shows that the increase in computing time for the 3-D HI-UMRT model relative to the 1-D UMRT model is moderate, since: 1) the computationally efficient UMRT engine is applied only to the perturbation equations with nontrivial solutions and 2) the layer parameters for the 1-D solution are reused for all higher perturbation orders. Numerical simulations using HI-UMRT based on 3-D cloud profiles simulated by the Weather Research and Forecasting numerical weather model illustrate the convergence of the iterative perturbation series. An intercomparison of the top-of-atmosphere brightness temperature images for HI-UMRT versus the slant path UMRT model illustrates the considerable impact of cloud horizontal inhomogeneities on the computed upwelling microwave radiances.