|
Figure 1.
Location of the Loess Plateau. (a) The simulation domain which is the source area in our study. The color shading denotes the Leaf Area Index (LAI) (m
2
m
−
2
) for 2018 from the GLASS data sets. (b) The topography of Loess Plateau which is the sink area. The black triangles show the locations of the China Meteorological Administration (CMA) stations.
Figure 2.
The conceptual diagram for this study. The flowchart of this study. P, Precipitation; E, Evaporation; ER, Local recycled moisture;
P
o
, Precipitation originated from oceanic sources;
P
t
, Precipitation originated from terrestrial sources;
ε
, Evaporation recycling ratio;
ω
, Contribution ratio; LAI, Leaf Area Index; RH, Relative humidity; Ta, Air temperature; Rn, Net radiation; SM, Soil moisture; WS, Wind speed; NINO, Niño3.4 SST Index; DMI, Dipole Mode Index; LP, Loess Plateau.
Figure 3.
Spatial distribution of (a–c) the linear trend of averaged LAI for the annual, rainy season, and dry season after the Grain for Green Project (2000–2019), and (d–f) time series of regional averaged LAI over the entire Loess Plateau. Black dots and stars indicate that the trend is significant (Mann‐Kendall test,
p
‐value
<
0.05).
Figure 4.
Time series of regional averaged (a) precipitation (
P
LP
)
, (b) evaporation (
E
LP
)
, (c) locally recycled moisture (
ER
LP
)
, (d) evaporation that flows out of the Loess Plateau (
E
out
), (e) contribution ratio (
ω
LP
) and (f) evaporation recycling ratio (
ε
LP
) for the entire Loess Plateau. Blue lines represent trends before and after the Grain for Green Project (none of them are significant). Shaded areas denote the spatial standard deviation. Star indicates that the trend is significant. The year 1992 was removed from the time series in this study, because the precipitation data for that year were anomalous high (Figure S2 in Supporting Information
S1
).
Figure 5.
Spatial distribution of (a–c) mean annual recycled moisture (ER), contribution ratio (
ω
), and evaporation recycling ratio (
ε
) during 2000–2019; (d–f) the difference in mean annual ER,
ω
, and
ε
before and after the project; (g–i) the linear trend of ER,
ω
, and
ε
during 1982–2000; (j–l) the linear trend of ER,
ω
, and
ε
during 2000–2019.
Figure 6.
Precipitationsheds of (a–c) the annual, rainy season and dry season during 1982–2019. The pie charts show the percentage of different moisture sources. (d–f)The difference in precipitationshed before and after the project. Bars on the right display the area change of the precipitationshed, and bars at the bottom show the changes of the moisture from different sources that comprise precipitation on the Loess Plateau before and after the project (land* means land excluding the LoessPlateau).
Figure 7.
The importance of LAI on water cycling in Loess Plateau, ranked by the Stepwise Selection method. The plus sign(“
+
”) denotes the forward selection and the minus sign (“
−
”) denotes backward selection.
∆
P
LP
,
∆
E
LP
, and
∆
ER
LP
represent the variance of the regional‐averaged
P
,
E
and
ER
, which were calculated as the differences between the values of successive years.
Figure 8.
The attribution of environmental factors to the change of
P
LP
,
E
LP
, and
ER
LP
.
Figure 9.
The trends of the regional effective values (
X
All
), regional averaged values(
X
LP
) and local effective values (
X
LP
) for different variables.
Figure 10.
|
关注我们
