I have been working as research assistant in USDA Forest Service since 2008. My function is to maintain and improve the functionality and efficiency of iTree Hydro. iTree Hydro is one of the 11 iTree tools (http://www.itreetools.org/) to assess tree cover and impervious cover influence on stream water flow quality and quantity. iTree Hydro is a physically-based semi-distributed watershed scale hydrology model. It applies TOPMODEL concept and specially is incorporated with tree and impervious hydro processes. It is coded in C++.
My previous research topics closely related to iTree-Hydro, which include cold climate hydrology, hydrograph simulation and microclimate simulation.
Cold climate hydrology:
We added cold climate hydrology routines to iTree-Hydro to simulate snow interception, snow unloading from trees, snow accumulation, snow sublimation, and snowmelt. Now it can be applied to both warm and cold area where snow significantly contribute to stream flow.
We developed a 2-parameter surface flow diffusion hydrograph model. it is derived based on the analytical solution of the advection-diffusion equation which describes channel or surface flow. The 2 time parameters are based on watershed scale, flow diffusivity and flow celerity and control the shape of the hydrograph and time to the discharge peak. Applications of the 2-parameter surface flow diffusion model on urban watersheds showed it can simulate hydrograpy timing and peak discharge as well rising and falling limb inflection points.
Microclimate, especially air temperature and humidity, significantly affect human thermal comfort, ecosystem services, and building energy use. Air temperature and humidity measurements are generally recorded at fixed-location meteorology stations, which do not represent the spatial variations encountered in these parameters across the landscape. We developed a spatial air temperature and humidity model to simulate local air temperature and humidity over a region where the mesoscale climate is presumed homogeneous. The model assumes that under the same mesoscale climate, microclimate is modified by local topography and land cover, which are two critical factors determining the absorbed solar radiation and the partitioning of sensible and latent heat. Therefore, the difference in microclimates among local clusters can be determined by the differences in local topography and land cover. Given a reference site where the meteorological data are collected, the microclimate of any other local cluster can be obtained by comparing the topography and land cover of the reference site and the local cluster. The model can be applied on strategic urban reforestation designs, urban heat island mitigation, climate change mitigation and adaptation, and ecosystem interaction research.