Key Points:• ECOSTRESS is a state-of-the-art combination of thermal bands, spatial and temporal resolutions, and measurement accuracy and precision • Data from 82 eddy covariance sites were coalesced concurrently with the first year of ECOSTRESS for Stage 1 validation • Clear-sky ET from ECOSTRESS compared well against a wide range of eddy Abstract The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) was launched to the International Space Station on 29 June 2018 by the National Aeronautics and Space Administration (NASA). The primary science focus of ECOSTRESS is centered on evapotranspiration (ET), which is produced as Level-3 (L3) latent heat flux (LE) data products. These data are generated from the Level-2 land surface temperature and emissivity product (L2_LSTE), in conjunction with ancillary surface and atmospheric data. Here, we provide the first validation (Stage 1, preliminary) of the global ECOSTRESS clear-sky ET product (L3_ET_PT-JPL, Version 6.0) against LE measurements at 82 eddy covariance sites around the world. Overall, the ECOSTRESS ET product performs well against the site measurements (clear-sky instantaneous/time of overpass: r 2 = 0.88; overall bias = 8%; normalized root-mean-square error, RMSE = 6%). ET uncertainty was generally consistent across climate zones, biome types, and times of day (ECOSTRESS samples the diurnal cycle), though temperate sites are overrepresented. The 70-m-high spatial resolution of ECOSTRESS improved correlations by 85%, and RMSE by 62%, relative to 1-km pixels. This paper serves as a reference for the ECOSTRESS L3 ET accuracy and Stage 1 validation status for subsequent science that follows using these data.

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We studied the altitudinal patterns of plant species richness and examined the effects of geometric constraints, area, and climatic factors on the observed richness patterns along the ridge of the Baekdudaegan Mountains, South Korea. Rapoport's altitudinal rule was evaluated by examining the relationship between altitudinal range size and midpoint. We also examined the latitudinal effect on species richness. Plant data were collected from 1,100 plots along a 200–1,900 m altitudinal gradient along the ridge of the Baekdudaegan. A total of 802 plant species from 97 families and 342 genera were found. The altitudinal patterns of plant species richness along the ridge of the Baekdudaegan depicted distinctly hump‐shaped patterns, although the absolute altitudes of the richness peaks vary somewhat among plant groups. While the mid‐domain effect (MDE) was the most powerful explanatory variable in simple regression models, species richness was also associated with climatic factors, especially mean annual precipitation (MAP) and temperature (MAT) in multiple regression models. The relative importance of the MDE and climatic factors were different among plant groups. The MDE was more important for woody plants and for large‐ranged species, whereas climatic factors were better predictors for total and herbaceous plants and for small‐ranged species. Rapoport's altitudinal rule and a latitudinal effect on species richness were not supported. Our study suggests that a combined interaction of the MDE and climatic factors influences species richness patterns along the altitudinal gradient of the Baekdudaegan Mountains, South Korea.

Background: It is important to quantify changes in CO 2 sources and sinks with land use and land cover change. In the last several decades, carbon sources and sinks in East Asia have been altered by intensive land cover changes due to rapid economic growth and related urbanization. To understand impact of urbanization on carbon cycle in the monsoon Asia, we analyze net CO 2 exchanges for various land cover types across an urbanization gradient in Korea covering high-rise high-density residential, suburban, cropland, and subtropical forest areas. Results: Our analysis demonstrates that the urban residential and suburban areas are constant CO 2 sources throughout the year (2.75 and 1.02 kg C m −2 year −1 at the urban and suburban sites), and the net CO 2 emission indicate impacts of urban vegetation that responds to the seasonal progression of the monsoon. However, the total random uncertainties of measurement are much larger in the urban and suburban areas than at the nonurban sites, which can make it challenging to obtain accurate urban flux measurements. The cropland and forest sites are strong carbon sinks because of a double-cropping system and favorable climate conditions during the study period, respectively (− 0.73 and − 0.60 kg C m −2 year −1 at the cropland and forest sites, respectively). The urban area of high population density (15,000 persons km −2) shows a relatively weak CO 2 emission rate per capita (0.7 t CO 2 year −1 person −1), especially in winter because of a district heating system and smaller traffic volume. The suburban area shows larger net CO 2 emissions per capita (4.9 t CO 2 year −1 person −1) because of a high traffic volume, despite a smaller building fraction and population density (770 persons km −2). Conclusions: We show that in situ flux observation is challenging because of its larger random uncertainty and this larger uncertainty should be carefully considered in urban studies. Our findings indicate the important role of urban vegetation in the carbon balance and its interaction with the monsoon activity in East Asia. Urban planning in the monsoon Asia must consider interaction on change in the monsoon activity and urban structure and function for sustainable city in a changing climate.

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