My current research involves using multi-platform observations to improve our understanding about the global budget of atmospheric methane (CH4), a potent greenhouse gas.

  • Inverse analysis of anthropogenic and natural emissions of methane using satellite and ground-based observations
  • Monitor global hydroxyl radical concentration with satelllite observations of atmospheric methane [paper]
  • Identification of global oil&gas methane emission hotspot




Previous Project

enhanced brown carbon at high altitudes

Upper Tropospheric Brown Carbon and Its Radiative Impact

Nature Geosciences, 2017 

Using a unique set of aircraft measurements, we show that atmospheric BrC, a little-understood absorbing agent in the atmosphere, is more dynamic than previously thought. We found BrC is prevalent in the upper troposphere and causes disproportionately strong warming. Evidence suggests that convection may serve as the medium for generating and transporting BrC.


LongTerm Ozone Trend

Long-term Ozone Records and Impact of Climate

Proceedings of the National Academy of Sciences, 2016 [paper]

Despite the emission reduction in last three decades, surface ozone during October has not seen a decreasing trend over the Southeast US, in constrast to the decreasing trend in the summer. The October surface ozone correlates well with vapor pressure deficit, a humidity measure, suggesting that a humidity-related mechanism controls ozone concentration in the fall season.


NOx gradient in the PBL

Vertical Distribution of Pollutants

Journal of Geophysical Research-Atmospheres, 2016 [paper]

In contrast to the popular well-mixed boundary layer assumption, we find a significant gradient of nitrogen oxides, important precursors of ozone pollution, in the boundary layer. The magnitude of the gradient is sensitive to the atmospheric stability. The finding has strong implications to the calculation of ozone production rate and satellite retrieval.



MSA chemistry

Marine Sulfur Chemistry

Geophysical Research Letters, 2014 [paper]

Marine sulfur chemistry is a critical component of global climate system. Our study on a suite of aircraft measurements taken in the Tropical Pacific identifies unknown sources of methanesulfonic acid (MSA), an important yet not-well-studied sulfur-containing compound, near the ocean surface and in the free troposphere.

passive PAH sampler

Passive PAH Sampler

Environmental Pollution, 2011 [paper]

This novel design of passive sampler is able to characterize the vertical distribution of polycyclic aromatic hydrocarbons (PAHs) in the gas phase near the soil surface, helping researcher understand the air-soil exchange process.