latstudio.blogg.se - Siff 2018 and then there was light

#SIFF 2018 AND THEN THERE WAS LIGHT FULL#
#SIFF 2018 AND THEN THERE WAS LIGHT SERIES#

The weakened fitting performance may result from the lower magnitude of SIF and consequently higher impact of noise in GRA and SHR relative to more productive biomes. However, both shrubland (SHR) and grassland (GRA) under-predicted high values and overpredicted low values, although the mean value was well predicted (Figure S4). The regression slopes were close to one for these biomes as well as needleleaf forests (NF) and evergreen broadleaf forests (EBF).

sr −1 were observed for croplands (CRO), deciduous broadleaf forests (DBF), and savannas (SAV).

However, given that SIF itself is a very weak signal (typically 0.75 and RMSE ≤ 0.075 W m −2 Recent advances in satellite SIF retrieval has motivated a number of applications of SIF in ecological, hydrological, and agricultural areas at various spatiotemporal scales (Guanter et al., 2014 Joiner et al., 2014 Liu et al., 2017 Sun et al., 2015, 2017). Due to its unique mechanistic relationship with photosynthesis, combined with growing volumes of satellite-based measurements, SIF holds great promise for quantifying global photosynthesis (or gross primary production (GPP Frankenberg et al., 2011)). Solar-induced chlorophyll fluorescence (SIF) is an optical signal emitted when sunlight is absorbed by chlorophylls within the photosynthetic machinery and therefore provides a functional proxy for photosynthesis (Porcar-Castell et al., 2014). Potential applications with this data set include advancing dynamic drought monitoring and mitigation, informing agricultural planning and yield estimation in a more spatially explicit way, and providing a benchmark for upcoming satellite missions with SIF capabilities at higher spatial resolutions. The high-resolution and global contiguous coverage of this data set will greatly enhance the synergy between satellite SIF and photosynthesis measured on the ground at consistent spatial scales. Comparison with independent airborne SIF measurements revealed strong consistency, confirming the high quality of this new SIF data set. We combined machine learning algorithms with known physiological constraints for this effort.

#SIFF 2018 AND THEN THERE WAS LIGHT SERIES#

This study developed a novel high-resolution time series of spatially contiguous SIF for the globe, leveraging NASA's Orbiting Carbon Observatory-2 measurements.

#SIFF 2018 AND THEN THERE WAS LIGHT FULL#

These limitations impede the full capability of SIF for improving our understanding of dynamics of photosynthesis and its response to environmental changes (particularly in heterogeneous landscapes) to better support carbon source/sink attribution and verification. However, existing satellite SIF records are restricted to low spatial resolutions, sparse data acquisition, or both. Newly available observations of solar-induced chlorophyll fluorescence (SIF) from satellite sensors represent a major step toward quantifying photosynthesis globally in real time. Oco2_005 to detect drought would be diminished. Oco2_005 of needleleaf forests would be overestimated during autumn, and (3) the capability of Oco2_005 of croplands, deciduous temperate, and needleleaf forests would be underestimated during the peak season, (2) Further, without time and biome stratification, (1)

Oco2_005 with Chlorophyll Fluorescence Imaging Spectrometer airborne measurements revealed striking consistency ( R 2 = 0.72 regression slope = 0.96).

Oco2_005 accurately preserved the spatiotemporal variations of

This was achieved by stratifying biomes and times for training and predictions, which accounts for varying plant physiological properties in space and time. Oco2_005) using machine learning constrained by physiological understandings. This study developed a spatially contiguous global OCO-2 SIF product at 0.05° and 16-day resolutions ( Oco2_orbit), but its discontinuous spatial coverage precludes its full potential for understanding the mechanistic SIF-photosynthesis relationship. The Orbiting Carbon Observatory-2 (OCO-2) collects solar-induced chlorophyll fluorescence (SIF) at high spatial resolution along orbits (