A5035005147- Climate variability and models
- Plant Water Relations and Carbon Dynamics
- Geology and Paleoclimatology Research
- Remote Sensing in Agriculture
- Meteorological Phenomena and Simulations
- Groundwater and Isotope Geochemistry
- Hydrology and Drought Analysis
- Atmospheric and Environmental Gas Dynamics
- Plant responses to elevated CO2
- Isotope Analysis in Ecology
- Methane Hydrates and Related Phenomena
- Genomics and Phylogenetic Studies
- Cryospheric studies and observations
- Tropical and Extratropical Cyclones Research
- Precipitation Measurement and Analysis
- Geomagnetism and Paleomagnetism Studies
- Olfactory and Sensory Function Studies
- Oceanographic and Atmospheric Processes
- Climate change impacts on agriculture
- Geophysics and Gravity Measurements
- Atomic and Subatomic Physics Research
- Ionosphere and magnetosphere dynamics
- Arctic and Antarctic ice dynamics
- Atmospheric aerosols and clouds
- Nephrotoxicity and Medicinal Plants
Brown University
2015-2024
Korea Institute of Oriental Medicine
2019
John Brown University
2019
Jet Propulsion Laboratory
2012
University of Chicago
2009-2010
Planetary Science Institute
2007-2008
University of California, Berkeley
2007-2008
Inha University
1999
We have incorporated the cycling of water isotopes into NCAR atmospheric general circulation model, CAM2. Isotope dynamics mostly follow those previous isotope GCMs, with fractionation being produced by evaporation at surface and cloud processes. A new feature that we added is direct estimation degree isotopic equilibration between vapor raindrops as a function temperature rain rate. The model yields reasonable global pattern in precipitation, but detailed comparison observations limited...
Abstract Several studies have shown that satellite retrievals of solar‐induced chlorophyll fluorescence ( SIF ) provide useful information on terrestrial photosynthesis or gross primary production GPP ). Here, we incorporated equations coupling to in a land surface model, the National Center for Atmospheric Research Community Land Model version 4 NCAR CLM 4), and demonstrated its use as diagnostic tool evaluating calculation photosynthesis, key process model strongly influences carbon,...
Accurate estimation of terrestrial photosynthesis has broad scientific and societal impacts. Measurements can be used to assess plant health, quantify crop yield, determine the largest CO2 flux in carbon cycle. Long-term continuous monitoring vegetation optical properties provide valuable information about physiology. Recent developments remote sensing solar-induced chlorophyll fluorescence (SIF) spectroscopy have shown promising results using this photosynthetic activities stresses at...
Abstract Traditional methods of carbon monitoring in mountainous regions are challenged by complex terrain. Recently, solar‐induced fluorescence (SIF) has been found to be an indicator gross primary production (GPP), and the increased availability remotely sensed SIF provides opportunity estimate GPP across Western United States. Although empirical linkage between is strong, current mechanistic understanding this incomplete depends upon changes leaf biochemical processes which absorbed...
The application of water isotopes to estimate the glacial‐interglacial cycle temperature ( T ) assumes validity present‐day spatial relationship between a and δ 18 O in precipitation p temporal changes at fixed location. We explored how why annual mean − is different from one Our general circulation‐isotope model exhibits slope 1.22‰/°C top inversion layer i over Antarctica, comparable observed value 1.25‰/°C Dahe et al. (1999) using Phillpot Zillman (1970) surface layer. Over Southern Ocean...
Low latitude paleoclimate records from speleothem δ 18 O measurements are often considered to reflect variations in precipitation amounts. Here we test this interpretation with a water isotope enabled atmospheric general circulation model, comparing modern and Last Glacial Maximum (LGM) controls on the p Brazil. We argue that is determined by contributions local evaporation (high O) versus vapor convergence region (low O). Our analysis indicates amount effect, commonly used infer low...
Quantifying how global warming impacts the spatiotemporal distribution of precipitation represents a key scientific challenge with profound implications for human welfare. Utilizing monthly data from Coupled Model Intercomparison Project (CMIP3) climate change simulations, results here show that occurrence very dry (<0.5 mm/day) and wet (>10 months comprises straightforward, robust metric anthropogenic on tropical land region rainfall. In particular, differencing tropics‐wide frequency...
Tropical rainforests are known to exhibit low intraseasonal precipitation variability compared with oceanic areas similar mean in observations and models. In the present study, potential role of transpiration for this difference is investigated using National Center Atmospheric Research (NCAR) atmospheric general circulation model. Comparing model results without shows that absence transpiration, decreases as may be expected. However incidence both higher daily total column water more...
Angiosperms (flowering plants) have higher transpirational capacities than any other plants. Here we use climate model simulation to test the hypothesis that high capacity of angiosperms plays a unique role in maintenance tropical rainforest. Their elevated transpiration rates are shown increase recycling precipitation up ∼300 mm/yr (∼20% total precipitation) averaged over whole South America and wet season duration Amazon basin. Transpiration triggers convection by increasing moisture...
General circulation models (GCMs) predict that the global hydrological cycle will change in response to anthropogenic warming. However, these predictions remain uncertain, particular for precipitation [IPCC, 2013]. Held and Soden [2006] suggest as lower-tropospheric water vapor concentration increases a warming climate, atmospheric convective mass fluxes weaken. Unfortunately, this process is difficult constrain, are poorly observed incompletely simulated GCMs. Here, we demonstrate stable...
Abstract The expansion of C 4 grassland in the Neogene, starting from to 9 million years ago, is thought be caused by decreasing CO 2 concentration, increasing aridity, or a combination both. Oxygen isotopes paleoproxies show trend and an variability mid‐Miocene Pleistocene Southern Great Plains United States, where carbon indicate overall increase plants during same time period. Using isotope‐enabled General Circulation Model (GCM) simulations, here I explore causes long‐term oxygen...
Abstract Speleothem oxygen isotopes have been shown to exhibit a close relationship with summer insolation in the Northern Hemisphere, leading hypothesis that East Asian monsoon intensity is proportional insolation. This hypothesis, however, has questioned because previous climate model simulations unable simulate observed large variation precipitation or isotope values, about half of entire modern tropical regions, response change due precession cycle. Here we show new results, using fully...
Abstract The proxy record of global temperature shows that the dominant periodicity glacial cycle shifts from 40 kyr (obliquity) to 100 (eccentricity) about a million years ago. Using climate model simulations, here we show pace depends on pattern hemispheric sea ice growth. In cold grows asymmetrically between two hemispheres under changes Earth's orbital precession, because growth potential outside Arctic Circle is limited. This difference in leads an asymmetry absorbed solar energy for...
Characterizing the spatiotemporal patterns of ecosystem responses to drought is important in understanding impact water stress on tropical ecosystems and projecting future land cover transitions East African tropics. Through analysis satellite measurements solar-induced chlorophyll fluorescence (SIF) normalized difference vegetation index (NDVI), soil moisture, rainfall, reanalysis data, here we characterize 2010–2011 Africa. The included consecutive failure rainy seasons...
Abstract The rotation of Earth breaks time-reversal and reflection symmetries in an opposite sense north south the equator, leading to a topological origin for certain atmospheric oceanic equatorial waves. Away from rotating shallow-water stably stratified primitive equations exhibit Poincaré inertia–gravity waves that have nontrivial topology as evidenced by their strict superinertial time scale phase singularity frequency–wavevector space. This then predicts, via principle bulk-interface...
Abstract The 2012–2016 California Drought severely impacted natural vegetation across a wide range of environmental gradient. Although several studies have reported an increase in plant water stress and mortality, the spatiotemporal variations ecosystem productivity responses associated biological drivers remain unclear. Here, using Enhanced Vegetation Index from Moderate resolution imaging spectrometer, we found that 45% ecosystems showed abrupt change (breakpoint [BP]) during 2012–2016....
Abstract The Amazon rainforest is known as the “Green Ocean” for its maritime‐like convection and cloud microphysics during wet season. Although previous studies suggest dominant thermodynamic processes involved in deep may differ between land ocean, a comprehensive understanding of thermodynamics Amazonian lacking. Using 404,971 daytime precipitating profiles from CloudSat satellite, we observe regime transition congestus dominance to cumulonimbus when convective available potential energy...
Abstract We investigated the interaction between surface conditions and precipitating convection by comparing Amazon River against surrounding forest. Despite similar synoptic within a few tens of kilometers, river is substantially cooler than forest during day warmer at night. analyzed 20 years high‐resolution satellite precipitation data confirmed previous findings daytime rainfall reduction over for whole Basin. The percentage strongest dry‐to‐wet transition season. In addition,...
Abstract Objectives The aim of the current study was to investigate effectiveness and clinical feasibility Biyeom‐go for treatment nasal symptoms associated with rhinitis. Design Prospective observational study. Setting This conducted at Woosuk Korean Medicine Medical Center in South Korea. Participants Fifty‐eight patients rhinitis participated this All received >3 times daily a total 4 weeks. Main outcome measures primary symptom score. Mini‐rhinoconjunctivitis quality life...
The nucleotide sequences of a 504 bp segment the mitochondrial cytochrome b gene were analyzed to survey intraspecific variation brown frog, Rana dybowskii, collected from nine populations in South Korea. Comparisons sequence divergence suggest that examined are clearly classified into two types (type 1 and type 2), diverged each other by high value 14.3–15.9% divergence. distributed allopatrically most populations, but only one population occurs sympatrically. In Tonghae population, their...
The Western US accounts for a significant amount of the forested biomass and carbon uptake within conterminous United States. Warming drying climate trends combined with legacy fire suppression have left forests particularly vulnerable to disturbance from insects, drought mortality. These challenging conditions may significantly weaken this region’s ability atmosphere warrant continued monitoring. Traditional methods monitoring are limited by complex terrain Rocky Mountains that lead...
The rotation of the earth breaks time-reversal and reflection symmetries in an opposite sense north south equator, leading to a topological origin for certain atmospheric oceanic equatorial waves. Away from equator rotating shallow water stably stratified primitive equations exhibit Poincare inertio-gravity waves that have nontrivial topology as evidenced by their strict superinertial timescale phase singularity frequency-wavevector space. This non-trivial then predicts, via principle...
Abstract As anthropogenic carbon emissions continue, it is important to predict how vegetation will change due the warming climate, increasing atmospheric CO 2 , and changing precipitation patterns. Some projections show decreases in either regionally tropics (e.g., Falloon et al., 2012; Port 2012) or globally Bastin 2019) high temperatures drying, there large uncertainty surrounding response of global climate (Arora 2020; Friedlingstein 2006; Walker 2020). Here we use simulations with NCAR...