Data from: Tropical Central African bomb radiocarbon reveals antiphase air-mass atmospheric fluxes and vegetation-growth relationships

To achieve more accurate Earth system model projections of diverse climate
scenarios, researchers need observation-based data on the movement of
carbon between reservoirs, and especially across tropical regions. The
Tropical Low-Pressure Belt (TLPB) is a key driver of atmospheric
circulation across lower latitudes. While the TLPB shifts across the
east–west extent of northern Africa, the extent to which 14C
concentrations apply to Afrotropical forests remains untested, restricting
our understanding about other carbon feedbacks. Here, we present a
high-precision atmospheric 14C record (1940–2012) from a lowland
tropical tree species (Entandrophragma utile) in Cameroon. We included 107
measurements from whole rings and 15 intra-annual slices. The
intra-annual 14C data from 1962, 1963, and 1964 confirm a 7-month
long growing season (April–November) with a photosynthetic profile typical
of Northern Hemisphere (NH) sites, and showing no
nonstructural-carbohydrate interference. The full 14C record
reveals that air masses reaching the site were derived primarily from
Southern Hemisphere (SH) readings followed by recycled bomb-14C signals
from soil and litter. Radiocarbon results were substantiated by HYSPLIT
model trajectories coupled with NCEP/NCAR reanalysis data. The paradox of
finding that tropical NH trees grow using 14CO2 of SH
air masses and land-surface respiration challenges existing
zonal 14C classifications. Our findings highlight an essential
role for robust observational 14C data in refining atmospheric
models and improving carbon-cycle assessments across distinct climate
zones.