Site: Bondville Portable Tower
Vegetation: Alternating crop (corn/soybean)- 2004 crop is corn
Latitude:40.00621?
Longitude:88.29041?
Elevation: 219.3 m
Leaf area index: see individual files for each year
flux system measuremen height: 10 m

Following is a list and units of data contained in the BP04_XXX.DAT files where XXX is the calender day of year.

Column		variable 		units
1		decimal day		-
2		calender day   		-
3 		hour            	-
4		wind speed 		m/s
5		wind direction		degrees
6		air temperature		degrees C
7		relative humidity	%
8		pressure		mb
9		incoming PAR		uE/m2/s
10		outgoing PAR		uE/m2/s
11		incoming global		W/m2
12		outgoing global		W/m2
13 		incoming longwave	W/m2
14 		outgoing longwave	W/m2
15 		net radiation 		W/m2 
16		ground heat flux	W/m2
17		wetness			-
18		precip 			mm
19		surface temperature	degrees C
20		soil temp (2 cm)	degrees C
21		soil temp (4 cm)	degrees C
22 		soil temp (8 cm)	degrees C
23 		soil temp (16 cm)	degrees C
24		soil temp (32 cm)	degrees C
25 		soil temp (64 cm)	degrees C
26              soil temp (128 cm)      degrees C
27 		u_bar (sonic)		m/s
28		momentum flux (u'w') 	m2/s2
29		u'2			m2/s2
30		v'2			m2/s2
31		w'2			m2/s2
32		sensible heat flux 	W/m2
33		latent heat flux	W/m2
34		CO2 flux 		mg CO2/m2/s
35		soil moisture (10 cm)   volumetric water content
36		soil moisture (20 cm)	volumetric water content
37		soil moisture (30 cm)   volumetric water content
38		soil moisture (40 cm)	volumetric water content
39		soil moisture (60 cm)   volumetric water content
40		soil moisture (100 cm)	volumetric water content