Sensitivity of CO₂ and CH₄ Annual Cycles to Different Meteorological Variables at a Rural Site in Northern Spain

Table 7

Differences between average concentrations calculated with observations selected for different thresholds of wind speed and the annual cycle for nighttime observations. Availabilities and numbers of days without observations (gaps) are presented.

Type of test	Wind speed threshold (m·s^−1)	Availability (%)	Gap (days)	CO2 difference		CH4 difference
				ppm	%	ppm	%
Above	9	11.1	182	−4.4	−1.10	−0.017	−0.91
	8	17.2	130	−3.8	−0.95	−0.014	−0.73
	7	25.4	85	−3.0	−0.75	−0.011	−0.57
	6	35.3	58	−2.7	−0.66	−0.007	−0.38
	5	47.0	20	−2.1	−0.53	−0.005	−0.27
	4	59.6	6	−1.7	−0.41	−0.005	−0.24
Below	2	11.1	136	3.5	0.88	0.013	0.68
	3	22.1	68	3.4	0.85	0.013	0.67
	4	35.9	24	2.5	0.63	0.009	0.47
	5	48.6	7	1.8	0.46	0.006	0.32
	6	60.3	2	1.3	0.33	0.005	0.25
	7	70.2	2	0.9	0.23	0.004	0.21