Figure 1.
Dynamic of climate factors in the period 1911–2000.
The variations of climatic variables were derived from CRU_TS 2.1 data. (a): mean annual temperature (MAT), (b): biological temperature (BT), (c): mean annual precipitation (MAP).
Figure 2.
Spatial distribution of global natural vegetaiton biomes in the period 1911–2000.
(a): T1 period (1911–1940), (b): T2 period (1941–1970), (c): T3 period (1971–2000). The different colors represent the different ecosystems, tundra & alpine steppe (12.85%), cold desert (1.56%), warm desert (13.93%), semi-desert (5.96%), savanna (17.66%), steppe (3.29%), temperate humid grassland (5.86%) and Forest (39.65%) in T3 period.
Table 1.
Areas of terrestrial ecosystems at continental levels in 1911–2000.
Figure 3.
Map showing the geographical distribution of detailed terrestrial NPP study sites.
The dataset are obtained from the Oak Ridge National Laboratory (ORNL), Distributed Active Archive Center database. • = grassland sites included in the present analysis; ▴ = NPP study sites forests (tropical forest, temperate forest and boreal forest), ★ and + = multi biomes – EDMI (B and C) data [63]. These data, and further information about the study sites, are publicly available at www.daac.ornl.gov/NPP/.
Figure 4.
Comparison of NPP value simulated by synthetic model and observed data (r = 0.9262, P<0.001).
The observed data are collected from the Oak Ridge National Laboratory (ORNL). These data, and further information about the study sites, are publicly available at www.daac.ornl.gov/NPP/.
Table 2.
Comparison of published values of present terrestrial net primary productivity (NPPT) and our research.
Table 3.
NPP of terrestrial ecosystems at continental levels in 1911-2000.
Figure 5.
Variations of terrestrial ecosystems NPP in climatic zones in the period 1911–2000.
(a): Tropical zone, (b): North frigid zone, (c): North temperate zone, (d): South temperate zone. South frigid zone was not involved in this research. TAS: tundra & alpine steppe; CD: Cold desert; SD: Semi-desert; SP: Steppe; THG: Temperate humid grassland; WD: warm desert; SV: savanna; TF: Tempearte forest; STF: Subtropical forest; TRF: Tropical forest.
Figure 6.
Proportion of different correlations between global NPP and MAP, MAT and BT.
ESNC is extremely significant negative correlation; SNC is significant negative correlation; NCNS is negative correlation but none significant; PCNS is positive correlation but none significant; SPC is significant positive correlation; ESPC is extremely significant positive correlation.