Long-Term (2007 to 2018) Energy and CO₂ Fluxes over an Agriculture Ecosystem in the Southeastern Margin of the Tibetan Plateau

Table 4

Correlation coefficients of the averaged sensible heat flux (Hs) and environmental variables including the averaged wind speed (WS) at 4 m height, temperature difference between the upper soil layer (at 4 cm depth) and the atmosphere (ΔT), the WS multiplied by ΔT (WS  ΔT), net radiation (Rn) at 1.5 m height, air temperature (Ta), the total precipitation (PPT), and the normalized difference vegetation index (NDVI) at multiple timescales from 2007 to 2018. There is no examination about the PPT at half-hourly timescales and the NDVI between half-hourly and daily timescales.

Timescales	Environmental variables
	WS	ΔT	WS  ΔT	Rn	Ta	PPT	NDVI
Half-hourly	0.01	−0.20	−0.10	0.83	0.31
Daily	−0.55	0.19	0.28	0.53	0.17	−0.13
Monthly	−0.75	0.38	0.48	0.26	0.27	0.25	−0.08
Yearly	−0.95	−0.39	−0.32	−0.39	−0.49	−0.10	0.03

Note: the asterisk () indicates the significance level of 0.05.