Atacama Large Millimeter Array

Weather Data

To measure the weather conditions at Llano de Chajnantor, ESO has two weather stations. These weather stations measure: Air Temperature, Relative Humidity, Solar Radiation, Atmospheric Pressure and Wind Speed & Direction.

Temperature/Time at Calama city

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Data Available

Notes:

The time resolution for the weather data is 1 hour.
A -999 in the data file means no value.
The data file structure (columns) is the following:
- Elapsed seconds since January 1st, 1980 00:00:00 UT
- Year day + fraction of the day (1 correspond to January 1st since the begining of day)
- Evaporation in mm of water as predicted by Priestly/Taylor model
- Relative humidity [%]
- Air Temperature [°C]
- Atmospheric Pressure [mbar], good within 5 mbars
- Wind speed [km/h]
- Wind speed [m/s]
- Solar radiation [J/m2 h]
- Solar radiation [W/m2 h]
- Wind direction [deg], measured clockwise from north
- Wind direction standard deviation in a period of 1 hour.

2005

Month Temperature Wind Speed Solar Radiation Relative Humidity Raw data
January 2005 x x x x x
February 2005 x x x x x
March 2005 x x x x x
April 2005 x x x x x
May 2005 x x x x x
June 2005 x x x x x
July 2005 x x x x x
August 2005
September 2005
October 2005
November 2005
December 2005
2005

2004

Month Temperature Wind Speed Solar Radiation Relative Humidity Raw data
January 2004 x x x x x
February 2004 x x x x x
March 2004 x x x x x
April 2004 x x x x x
May 2004 x x x x x
June 2004 x x x x x
July 2004 x x x x x
August 2004 x x x x x
September 2004 x x x x x
October 2004 x x x x x
November 2004 x x x x x
December 2004 x x x x x
2004 x x x x x

2003

Month Temperature Wind Speed Solar Radiation Relative Humidity Raw data
January 2003 x x x x x
February 2003 x x x x x
March 2003 x x x x x
April 2003 * NA NA NA NA NA
May 2003 x x x x x
June 2003 x x x x x
July 2003 x x x x x
August 2003 x x x x x
September 2003 x x x x x
October 2003 x x x x x
November 2003 x x x x x
December 2003 x x x x x
2003 x x x x x

2002

Month Temperature Wind Speed Solar Radiation Relative Humidity Raw data
January 2002* x x x x x
February 2002* x x x x x
March 2002 x x x x x
April 2002 x x x x x
May 2002 x x x x x
June 2002 x x x x x
July 2002 x x x x x
August 2002 x x x x x
September 2002 x x x x x
October 2002 x x x x x
November 2002 x x x x x
December 2002 x x x x x
2002 x x x x x

2001

Month	Temperature	Wind Speed	Solar Radiation	Relative Humidity	Raw data
January 2001	x	x	x	x	x
February 2001	x	x	x	x	x
March 2001	x	x	x	x	x
April 2001	x	x	x	x	x
May 2001	x	x	x	x	x
June 2001	x	x	x	x	x
July 2001	x	x	x	x	x
August 2001	x	x	x	x	x
September 2001	x	x	x	x	x
October 2001 *	x	x	x	x	x
November 2001	x	x	x	x	x
December 2001	x	x	x	x	x
2001	x	x	x	x	x

2000

Month	Temperature	Wind Speed	Solar Radiation	Relative Humidity	Raw data
January 2000	x	x	NA	x	CBI Data
February 2000	x	x	NA	x	CBI Data
March 2000	x	x	NA	x	CBI Data
April 2000	x	x	NA	x	CBI Data
May 2000	x	x	NA	x	CBI Data
June 2000	x	x	NA	x	CBI Data
July 2000	x	x	NA	x	CBI Data
August 2000	x	x	NA	x	CBI Data
September 2000	x	x	NA	x	CBI Data
October 2000	x	x	x	x	x
November 2000	x	x	x	x	x
December 2000	x	x	x	x	x
2000	x	x	x	x	x

1999

Month	Temperature	Wind Speed	Solar Radiation	Relative Humidity	Raw data
January 1999	x	x	x	x	x
February 1999	x	x	x	x	x
March 1999	x	x	x	x	x
April 1999	x	x	x	x	x
May 1999	x	x	x	x	x
June 1999	x	x	x	x	x
July 1999	x	x	x	x	x
August 1999	x	x	x	x	x
September 1999	x	x	x	x	x
October 1999	x	x	x	x	x
November 1999	x	x	x	x	x
December 1999	x	x	x	x	x
1999	x	x	x	x	x

1998

Month	Temperature	Wind Speed	Solar Radiation	Relative Humidity	Raw data
June 1998	x	x	x	x	x
July 1998	x	x	x	x	x
August 1998	x	x	x	x	x
September 1998	x	x	x	x	x
October 1998	x	x	x	x	x
November 1998	x	x	x	x	x
December 1998	x	x	x	x	x
1998	x	x	x	x	x

Note 1: During 1998, ESO weather station C was used.
Note 2: Wind direction is not available for January 1999, March 2002 and April 2002 due to malfunctioning of the sensor.
Note 3: The weather data available for January 1999 was acquired with ESO weather station B.
Note 4: Weather data for April 1999 was acquired with ESO weather station C for the period UTC days 91-106, and ESO weather station B for the period UTC days 106-120. This weather station is used during the following months.
Note 5: "*" Not all data available