About

Xiquan Dong is a Professor of Hydrology and Atmospheric Sciences, with additional expertise in Remote Sensing and Spatial Analysis. He received his Ph.D. in Meteorology from Pennsylvania State University in 1996 and subsequently worked at NASA Langley Research Center. Since 2002, he has been a faculty member at the University of North Dakota, where he manages a research group that has grown significantly over the years. His research focuses on developing advanced cloud retrieval techniques in ground-based remote sensing, validating satellite cloud retrievals using ground-based data, improving the simulation of clouds, radiation, and precipitation in GCM/WRF models and reanalyses, and investigating regional extreme weather events and their feedback processes. His work has been supported by various agencies including DOE, NASA, NOAA, and NSF, and has contributed to improving climate model simulations using satellite observations. In addition to his research, Professor Dong is actively involved in community service, serving as a member of the Global Energy Balance Working Group of the International Radiation Commission, co-chairing NASA's Energy and Water Cycle Study Working Group, and serving as an associate editor for the Journal of Geophysical Research – Atmospheres and as an editor for Advances in Atmospheric Sciences. He teaches courses in physical meteorology, atmospheric remote sensing, and physical climate for both graduate and undergraduate students.

Research topics

• Atmospheric sciences
• Environmental science
• Meteorology
• Physics
• Climatology
• Geology
• Astrophysics
• Geography
• Oceanography

Selected publications

• Analysis of CCCma Radiative Transfer Calculations for Single‐Layer Overcast Ice Clouds

  Journal of Geophysical Research Atmospheres · 2026-04-21

  article

  Abstract Understanding interactions between incoming shortwave (SW) solar radiation and clouds is essential for quantifying and modeling Earth's Radiation Budget (ERB). Ice clouds are particularly problematic due to their wide variability in crystal habits, sizes, and shapes. In this study, data from NASA's Cloud and Earth Radiative Energy System (CERES) are used to identify single‐layer overcast ice clouds and calculate surface and top‐of‐atmosphere (TOA) SW fluxes using the Canadian Centre for Climate Modeling and Analysis (CCCma) Radiative Transfer Model (RTM). A total of 361 SW flux observations from 11 surface sites spanning different climatic regions, together with CERES SYN1deg satellite observations at the TOA, are used to evaluate the CCCma RTM's performance. The CCCma RTM exhibits mean bias errors (MBEs) of +3.7 W m −2 at the surface and +4.1 W m −2 at the TOA, with root mean square errors (RMSEs) of 72.7 and 33.2 W m −2 , respectively. Correspondingly, the CERES SYN1deg Fu‐Liou RTM shows MBEs of −12.1 and +18.5 W m −2 and RMSEs of 75.0 and 34.5 W m −2 for surface and TOA, respectively. MBE differences between the two RTMs are due to differing treatments of model physics, while their larger RMSEs at the surface result from both imprecise inputs and spatial variabilities of both inputs and surface observed flux.

  PublisherDOI

• Analysis of CCCma Radiative Transfer Calculations for Low‐Level Overcast Liquid Clouds Over ARM SGP and ENA Sites

  Journal of Geophysical Research Atmospheres · 2025-09-06 · 2 citations

  articleCorresponding

  Abstract This study uses the Canadian Centre for Climate Modeling and Analysis (CCCma) radiative transfer model to estimate shortwave flux for low‐level overcast liquid clouds. Calculations are evaluated against measurements at the Atmospheric Radiation Measurement Southern Great Plains (SGP, land) and Eastern North Atlantic (ENA, ocean) sites, as well as top of atmosphere (TOA) fluxes inferred from Clouds and Earth's Radiant Energy System (CERES) from 2014 to 2023. Mean observed surface (TOA) SW fluxes for the selected cases are 235.7 W m −2 (473.8 W m −2 ) at SGP and 348.7 W m −2 (356.4 W m −2 ) at ENA. Cloud microphysical properties retrieved from CERES MODIS are input into the CCCma using three assumed profiles: (a) cloud droplet effective radius ( r e ) and liquid water content (LWC) constant with height, (b) LWC and r e increasing linearly with height, and (c) LWC and r e increasing linearly from cloud base to ¾ height and then decreasing linearly up to cloud top. Overall, Method 3 produces the least error variance at both sites. At SGP, mean bias and root mean square error (RMSE) are −5.0 and 44.6 W m −2 at the surface and −4.6 and 25.4 W m −2 at TOA. At ENA, errors are +0.2 and 121.3 W m −2 at the surface and −8.0 and 26.1 W m −2 at TOA. Further screening cases with good agreement between satellite‐ and surface‐based cloud properties, RMSEs for surface fluxes decrease to 24.3 and 25.8 W m −2 at SGP and ENA. Comparisons with CERES Fu‐Liou calculations showed overall better performance by the CCCma, especially at ENA.

  PublisherDOI

• Quantifying the Differences in Southern Ocean Clouds Observed by Radar and Lidar From Three Platforms

  Geophysical Research Letters · 2025-05-04 · 1 citations

  articleOpen access1st authorCorresponding

  Abstract A synergistic analysis of the radar‐only and combined radar‐lidar observations across the three platforms was conducted. To align with well‐calibrated CloudSat cloud profiling radar (CPR) (and HCR) reflectivity measurements, a constant 4.5 dB offset was applied to all M‐WACR reflectivitives during the MARCUS. This brings M‐WACR data into better agreement with both HCR and CPR reflectivity measurements and facilitates a more reliable cloud fraction (CF) comparison. The total CFs (CF T s) derived from the three radars show excellent agreement. All three radars detect large drizzle drops, but M‐WACR and HCR excel at detecting smaller cloud droplets that are often missed by CPR. The underestimated CFs by CPR are due to increased attenuation of CPR measurements below 3 km, and the combined effects of attenuation and surface clutter below 1 km. Combining radar and lidar observations enhanced cloud detection by 20%–60%. The results from this study provide new insights for designing future cloud radar systems.

  PublisherOA PDFDOI

• Identifying MBL cloud boundaries and phase over the Southern Ocean using airborne radar and in-situ measurements during the SOCRATES campaign

  2025-06-02

  preprintOpen accessSenior author

  Abstract. The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) was an aircraft-based campaign (Jan 15 – Feb 26, 2018) using in-situ probes and remote sensors, targeting low-level clouds over the Southern Ocean (SO). A novel methodology was developed to identify cloud boundaries and classify cloud phases in marine boundary layer (MBL) clouds using airborne HIAPER Cloud Radar (HCR) and in-situ CDP+2D-S measurements. Cloud boundaries were determined using HCR reflectivity and spectrum width gradients. Single-layer low-level clouds accounted for ~85 % of observed cases. HCR-derived boundaries showed decent agreement with the Ceilometer and Micropulse lidar (MPL)-measurements during the Measurement of Aerosols, Radiation, and Clouds (MARCUS) ship-based campaign, with mean base and top differences of 0.04 km and 0.29 km. Additionally, HCR-derived cloud base heights correlated well (R = 0.78) with HSRL observations. A reflectivity–liquid water content (Z-LWC) relationship, LWC = 0.70Z0.29, was derived to retrieve LWC and liquid water path (LWP) from HCR profiles. The estimated LWP closely matched MARCUS microwave radiometer (MWR) retrievals, with a mean difference of 9.24 g/m². Cloud phase was classified using HCR-measurements, temperature, and LWP. Among single-layered LOW clouds, 48.8 % were classified as liquid, 23.3 % mixed-phase, and 6.9 % ice, with additional categories identified: drizzle (16.2 %), rain (3.4 %), and snow (1.5 %). The classification algorithm demonstrated over 90 % agreement with established phase detection methods. This study provides a robust framework for boundary and phase detection of MBL clouds, offering valuable insights into cloud microphysical processes over the SO and supporting future efforts in satellite algorithm development and climate model evaluation.

  PublisherDOI

• Supplementary material to "Identifying MBL cloud boundaries and phase over the Southern Ocean using airborne radar and in-situ measurements during the SOCRATES campaign"

  2025-06-02

  preprintOpen accessSenior author
  PublisherDOI

• Marine Boundary Layer Cloud Boundaries and Phase Estimation Using Airborne Radar and In Situ Measurements During the SOCRATES Campaign over Southern Ocean

  Atmosphere · 2025-10-16

  articleOpen accessSenior authorCorresponding

  The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) was an aircraft-based campaign (15 January–26 February 2018) that deployed in situ probes and remote sensors to investigate low-level clouds over the Southern Ocean (SO). A novel methodology was developed to identify cloud boundaries and classify cloud phases in single-layer, low-level marine boundary layer (MBL) clouds below 3 km using the HIAPER Cloud Radar (HCR) and in situ measurements. The cloud base and top heights derived from HCR reflectivity, Doppler velocity, and spectrum width measurements agreed well with corresponding lidar-based and in situ estimates of cloud boundaries, with mean differences below 100 m. A liquid water content–reflectivity (LWC-Z) relationship, LWC = 0.70Z0.29, was derived to retrieve the LWC and liquid water path (LWP) from HCR profiles. The cloud phase was classified using HCR measurements, temperature, and LWP, yielding 40.6% liquid, 18.3% mixed-phase, and 5.1% ice samples, along with drizzle (29.1%), rain (3.2%), and snow (3.7%) for drizzling cloud cases. The classification algorithm demonstrates good consistency with established methods. This study provides a framework for the boundary and phase detection of MBL clouds, offering insights into SO cloud microphysics and supporting future efforts in satellite retrievals and climate model evaluation.

  PublisherOA PDFDOI

• Radiance-to-irradiance conversion in the visible and near-infrared bands under clear-sky conditions

  Journal of Quantitative Spectroscopy and Radiative Transfer · 2025-11-27

  article
  PublisherDOI

• Estimating cloud boundaries, phase, and macrophysical properties of low-level clouds using in-situ and radar measurements over the Southern Ocean during the SOCRATES campaign

  2025-02-06

  preprintOpen accessSenior author

  The Southern Ocean (SO) provides a unique natural laboratory for studying cloud formation and cloud-aerosol interactions with minimal anthropogenic influence. The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES), was an aircraft-based campaign conducted from Jan 15 to Feb 28, 2018, off the coast of Hobart, Tasmania, utilizing the NSF/NCAR GV research aircraft. The aircraft was equipped with in-situ probes and remote sensors to observe precipitation, cloud particles, and aerosols, providing detailed vertical profiles to characterize the marine boundary layer (MBL) and free troposphere.

  PublisherOA PDFDOI

• Analysis of CCCma radiative transfer calculations for low level overcast liquid clouds over ARM SGP and ENA sites

  2025-04-17

  preprintOpen access

  This study evaluates the Canadian Centre for Climate Modeling and Analysis (CCCma) radiative transfer model (RTM) to estimate shortwave (SW) fluxes at both the surface and top of atmosphere (TOA) for low-level overcast liquid clouds. Calculations are evaluated against measurements at the ARM Southern Great Plains (SGP, land) and Eastern North Atlantic (ENA, ocean) sites, as well as TOA fluxes inferred from NASA CERES. Mean observed surface (TOA) SW fluxes for the selected cases are 235.7 W m-² (473.8 W m-²) at SGP and 348.7 W m-² (356.4 W m-²) at ENA. Cloud microphysical properties retrieved from CERES MODIS are input into the CCCma using three assumed profiles: (1) cloud droplet effective radius (re) and liquid water content (LWC) constant with height; (2) LWC and re increasing linearly with height; and (3) LWC and re increasing linearly from cloud base to ¾ height and then decreasing linearly up to cloud top. Overall, Method 3 produces the best results at both sites. At SGP, mean biases (RMSE) are -5.0 W m-² (44.6 W m-²) at the surface and -4.6 W m-2 (25.4 W m-²) at TOA. At ENA, errors are +0.2 W m-² (121.3 W m-²) at the surface and -8.0 W m-² (26.1 W m-²) at TOA. Further screening cases with good agreement between satellite- and surface-based cloud properties, RMSEs for surface fluxes decrease to 24.3 and 25.8 W m-² at SGP and ENA. Comparisons with CERES Fu-Liou calculations showed overall better performance by the CCCma, especially at ENA.

  PublisherOA PDFDOI

• Radiance-to-Irradiance Conversion in the Visible and Near-Infrared Bands Under Clear-Sky Conditions

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

Recent grants

• Collaborative Research: Evaluating the Influences of Aerosols on Low-level Cloud-precipitation Properties over Land and Ocean using Ground-based Observations and WRF Simulations

  NSF · $395k · 2017–2021

• Collaborative Research: Evaluation of Aerosol-Cloud-Radiation Processes and Feedbacks in the Alaskan Arctic

  NSF · $100k · 2007–2011

• Collaborative Research: Contrasting the Effects of Aerosols on Marine Boundary Layer (MBL) Cloud-precipitation Properties and Processes in Boreal and Austral Mid-latitude Regions

  NSF · $416k · 2020–2024

Frequent coauthors

• Baike Xi

  University of Arizona

  179 shared

• Peng Wu

  Harbin Normal University

  45 shared

• Patrick Minnis

  Northern Health and Social Care Trust

  39 shared

• Xiaojian Zheng

  University of Arizona

  30 shared

• Yuan Wang

  Stanford University

  29 shared

• Timothy Logan

  Texas A&M University

  27 shared

• Aaron Kennedy

  27 shared

• Yi Deng

  22 shared

Education

• Ph.D, Meteorology

  Pennsylvania State University

  1996

Awards & honors

• AAS Outstanding Editor Award for “Exceptional Contributions…