Satellite-Derived Global Monthly Trichodesmium Nitrogen Fixation Dataset (199709–202412)

Description :
This dataset provides global monthly estimates of Trichodesmium N2 fixation rates at a spatial resolution of 0.25° × 0.25° (latitude × longitude) for the period 1997–2024. The estimates were derived using a machine learning model (XGBoost) trained on a combination of in situ measurements of Trichodesmium N2 fixation and satellite-derived environmental variables, including sea surface temperature (SST), chlorophyll-a concentration (Chla), the diffuse attenuation coefficient at 490 nm [Kd(490)], and remote-sensing reflectance Rrs(λ) from OC-CCI bands (412, 443, 490, 510, 560, and 665 nm).

Each file corresponds to one month and contains a single variable: N2_fixation, representing the oceanic N2 fixation rate in units of µmol N m-2 d-1. The latitude and longitude coordinates are provided as one-dimensional variables (lat and lon). The temporal coverage of each file can be inferred from its filename in the format Trichodesmium_Nitrogen_fixation_YYYYMM_025deg.nc.

This dataset is suitable for studies of global oceanic nitrogen cycling, biogeochemical modeling, and analysis of spatiotemporal patterns of diazotrophic activity.

Spatial Coverage: Global oceans (-90° to 90° latitude, -180° to 180° longitude)
Temporal Coverage: Monthly, 1997.09–2024.12 (individual files per month)
Resolution: 0.25° × 0.25°
Variable: N2_fixation (µmol N m-2 d-1)