ChinaSpec: a Network for Long-term Ground-based Measurements of
Solar-induced Fluorescence in China
Abstract
Remotely sensed solar-induced fluorescence (SIF) has emerged as a novel
and powerful approach for terrestrial vegetation monitoring. Continuous
measurements of SIF in synergy with concurrent eddy covariance (EC) flux
measurements can provide a new opportunity to advance terrestrial
ecosystem science. Here we introduce a network of ground-based
continuous SIF observations at flux tower sites across the mainland
China referred to as ChinaSpec. The network consists of sixteen tower
sites including 6 cropland sites, 4 grassland sites, 4 forest sites and
2 wetland sites. An automated SIF system was deployed at each of these
sites to collect continuous high resolution spectra for high-frequency
SIF retrievals in synergy with EC flux measurements. The goal of
ChinaSpec is to provide long-term ground-based SIF measurements and
promote the collaborations between optical remote sensing and EC flux
observation communities in China. We present here the details of
instrument specifications, data collection and processing procedures,
data sharing and utilization protocols, and future plans. Furthermore,
we show the examples how ground-based SIF observations can be used to
track vegetation photosynthesis from diurnal to seasonal scales, and to
assist in the validation of fluorescence models and satellite SIF
products (e.g., from OCO-2 and TROPOMI) with the measurements from these
sites since 2016. This network of SIF observations could improve our
understanding of the controls on the biosphere-atmosphere carbon
exchange and enable the improvement of carbon flux predictions. It will
also help integrate ground-based SIF measurements with EC flux networks
which will advance ecosystem and carbon cycle researches globally.