Monday, January 31, 2011

Air Temperature Measurements [updated]

Quelccaya's automated weather station (AWS) is providing a unique perspective on the tropical mid-troposphere, documenting modern climate at one of the world’s most important high-elevation paleoclimate sites. Air temperature data from the station are now available through the links below.

History
A brief synopsis of paleoclimate research on Quelccaya Ice Cap (with images) is available here. A paper presenting the 2003 ice core record – spanning over 1,600 years – is well underway.

In conjunction with Quelccaya paleoclimate research, meteorological instrumentation was operated at several locations on the glacier through the late 1970s and early 1980s. The objective was to begin characterizing the largely-unknown climate at high elevations in the Andes, an effort carried out collaboratively with Stefan Hastenrath. Despite working with equipment that is considered rather unreliable by today’s standards, several publications resulted.

During the 2003 ice-core drilling expedition, meteorological measurements resumed – with modern electronics, satellite telemetry, and a new tower design. Images of the new AWS can be seen at the link above, and here.

AWS data
Measuring atmospheric properties is not trivial, especially when the goal is to assess any change in central tendency, variability, or extremes over time (i.e., climate). A set of ten climate monitoring principles proposed by Tom Karl at NOAA provides a succinct starting point to learn more about issues involved.

At the summit of Quelccaya Ice Cap the AWS is seen only by high-flying birds for all but a few days each year. Consequently, all data require considerable processing and inspection to insure that measurements are valid and meaningful, and free of systematic errors. This process is underway for AWS measurements from a comprehensive suite of sensors (see images).

The first data being made available from Quelccaya are air temperature measurements from highly-accurate sensors developed for NOAA’s Climate Reference Network (CRN). These sensors are identical to those used for the CRN system, resulting from years of development by NOAA's National Climatic Data Center and their Atmospheric Turbulence and Diffusion Division. For detailed information on CRN, as well as data access, click here.

Quelccaya data
The following links provide access to provisional air temperature data. Please be sure to read the metadata document.
  metadata (PDF)
  hourly values
  monthly values

UPDATE 3/25/2014:  A complete record of quality-controlled hourly air temperatures for July 2007-June 2009 are available here, as well as the accompanying metadata, and these values should be used rather than those above - which were provisional. The full 2007-13 period has been processed, yet these are not yet available due to insufficient fan speed during early-morning hours through a portion of this period. Maximum daily temperatures were largely unaffected and this series will be available soon. Thanks for your patience.]


Contact for any questions or comments:  dhardy@geo.umass.edu

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