A5101511623- Remote Sensing in Agriculture
- Remote Sensing and LiDAR Applications
- Plant Water Relations and Carbon Dynamics
- Indigenous Studies and Ecology
- Peatlands and Wetlands Ecology
- Land Use and Ecosystem Services
- Botany and Plant Ecology Studies
- Forest ecology and management
- Climate change and permafrost
- Urban Heat Island Mitigation
- Remote Sensing and Land Use
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Fire effects on ecosystems
- Leaf Properties and Growth Measurement
- Calibration and Measurement Techniques
- Meteorological Phenomena and Simulations
- Forest Ecology and Biodiversity Studies
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Ecology and Vegetation Dynamics Studies
- Conservation, Biodiversity, and Resource Management
- Species Distribution and Climate Change
- Geology and Paleoclimatology Research
- Wildlife Ecology and Conservation
Bay Area Environmental Research Institute
2020-2025
Ames Research Center
2020-2024
National Institute of Environmental Research
2016-2023
NASA Research Park
2023
Boston University
2014-2020
Royal Netherlands Meteorological Institute
2020
National Centre for Atmospheric Science
2020
University of East Anglia
2020
Bank for International Settlements
2017-2020
GEOMAR Helmholtz Centre for Ocean Research Kiel
2019
Monitoring and understanding climate-induced changes in the boreal arctic vegetation is critical to aid prognosticating their future. We used a 33 year (1982–2014) long record of satellite observations robustly assess metrics growing season (onset: SOS, end: EOS length: LOS) seasonal total gross primary productivity. Particular attention was paid evaluating accuracy these by comparing them multiple independent direct indirect productivity measures. These comparisons reveal that derived...
The aim of this paper is to assess the latest version MODIS LAI/FPAR product (MOD15A2H), namely Collection 6 (C6). We comprehensively evaluate through three approaches: validation with field measurements, intercomparison other products and comparison climate variables. Comparisons between ground measurements C6, as well C5 indicate: (1) LAI closer true than effective LAI; (2) C6 considerably better RMSE decreasing from 0.80 down 0.66; (3) both overestimate FPAR over sparsely-vegetated areas....
As the latest version of Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction Photosynthetically Active Radiation (FPAR) products, Collection 6 (C6) has been distributed since August 2015. This collection is evaluated in this two-part series with goal assessing product accuracy, uncertainty consistency previous version. In first paper, we compare C6 (MOD15A2H) 5 (C5) to check for discuss scale effects associated changing spatial resolution between two...
Abstract Seasonality in photosynthetic activity is a critical component of seasonal carbon, water, and energy cycles the Earth system. This characteristic consequence plant's adaptive evolutionary processes to given set environmental conditions. Changing climate northern lands (>30°N) alters state climatic constraints on plant growth, therefore, changes seasonality carbon accumulation are anticipated. However, how evolved its current state, what role their variability played this process...
Resolving the debate surrounding nature and controls of seasonal variation in structure metabolism Amazonian rainforests is critical to understanding their response climate change. In situ studies have observed higher photosynthetic evapotranspiration rates, increased litterfall leaf flushing during Sunlight-rich dry season. Satellite data also indicated greenness level, a proven surrogate carbon fixation, area season relative wet Some recent reports suggest that display no variations...
Leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) absorbed by vegetation have been successfully generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) data since early 2000. As Visible Infrared Radiometer Suite (VIIRS) instrument onboard, Suomi National Polar-orbiting Partnership (SNPP) has inherited scientific role MODIS, development a continuous, consistent, well-characterized VIIRS LAI/FPAR set is critical to continue MODIS time series. In...
The operational Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) algorithm has been successfully implemented for Visible Infrared Imager Radiometer Suite (VIIRS) observations optimizing a small set configurable parameters in Look-Up-Tables (LUTs). Our preliminary evaluation showed reasonable agreement between VIIRS MODIS LAI/FPAR retrievals. However, there is need more comprehensive...
Leaf scattering spectrum is the key optical variable that conveys information about leaf absorbing constituents from remote sensing. It cannot be directly measured space because radiation scattered leaves affected by 3D canopy structure. In addition, some specularly reflected at surface of leaves. This portion partly polarized, does not interact with pigments inside and therefore contains no its interior. Very little empirical data are available on spectral angular properties surfaces....
Abstract Constraining an increase in global mean temperature below 2°C compared to pre‐industrial levels is critical limiting dangerous and cascading impacts of anthropogenic climate change. Understanding future climatic changes their spatial heterogeneity at warming thus important for policy makers prepare actionable adaptation mitigation plans by identifying where what extent lives livelihoods will be impacted. This study uses the recently released NASA Earth eXchange Global Daily...
The Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) product is critical for global terrestrial carbon monitoring and ecosystem modeling. However, MODIS LAI calculated on a pixel-by-pixel day-by-day basis without using spatial or temporal correlation information, which leads to its high sensitivity of uncertainties in observed reflectance resulting an increased noise level time series. While exploiting prior knowledge common practice fill gaps observations, little...
Abstract. Most scenarios from integrated assessment models (IAMs) that project greenhouse gas emissions include the use of bioenergy as a means to reduce CO2 or even achieve negative (together with CCS – carbon capture and storage). The potential amount can be removed atmosphere depends, among others, on yields crops, land available grow these crops efficiency which produced by combustion is captured. While crop simulated models, estimates spatial distribution under current technology based...
Vegetation above-ground biomass (AGB) arises from a complex interaction between species composition and soil properties, water availability, solar radiation, the atmosphere. Light Detection Ranging (LiDAR) surveying technology has been ultimate method for quantifying structural properties of vegetation. Here, we study spatial structure AGB tropical temperate forest in Brunei Darussalam Republic Korea, respectively, using high-resolution LiDAR datasets. We were able to extract new information...
Abstract. Leaf area index is an important metric for characterising the structure of vegetation canopies and scaling up leaf plant processes to assess their influence on regional global climate. Earth observation estimates have increased in recent decades, providing a valuable resource monitoring changes evaluating representation land surface earth system models. The study presented here uses satellite products quantify variations seasonal timing value trough, peak, amplitude, evaluate how...
Abstract. The latest generation of geostationary satellites provide Earth observations similar to widely used polar orbiting sensors but at intervals as frequently every 5–10 minutes, making them ideal for studying diurnal dynamics land-atmosphere interactions. NASA Exchange (NEX) group created the GeoNEX datasets by collating data from several platforms, including GOES-16/17/18, Himawari-8/9, and GK-2A, placing on a common grid facilitate use science community. Here, we document Coincident...