Articles | Volume 5, issue 2
https://doi.org/10.5194/gi-5-451-2016
https://doi.org/10.5194/gi-5-451-2016
Research article
 | 
29 Sep 2016
Research article |  | 29 Sep 2016

The Niwot Ridge Subalpine Forest US-NR1 AmeriFlux site – Part 1: Data acquisition and site record-keeping

Sean P. Burns, Gordon D. Maclean, Peter D. Blanken, Steven P. Oncley, Steven R. Semmer, and Russell K. Monson

Abstract. The Niwot Ridge Subalpine Forest AmeriFlux site (US-NR1) has been measuring eddy-covariance ecosystem fluxes of carbon dioxide, heat, and water vapor since 1 November 1998. Throughout this 17-year period there have been changes to the instrumentation and improvements to the data acquisition system. Here, in Part 1 of this three-part series of papers, we describe the hardware and software used for data-collection and metadata documentation. We made changes to the data acquisition system that aimed to reduce the system complexity, increase redundancy, and be as independent as possible from any network outages. Changes to facilitate these improvements were (1) switching to a PC/104-based computer running the National Center for Atmospheric Research (NCAR) In-Situ Data Acquisition Software (NIDAS) that saves the high-frequency data locally and over the network, and (2) time-tagging individual 10 Hz serial data samples using network time protocol (NTP) coupled to a GPS-based clock, providing a network-independent, accurate time base. Since making these improvements almost 2 years ago, the successful capture of high-rate data has been better than 99.98 %. We also provide philosophical concepts that shaped our design of the data system and are applicable to many different types of environmental data collection.

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Short summary
The hardware and software used to collect eddy-covariance ecosystem fluxes of carbon dioxide, heat, and water vapor at a high-elevation subalpine forest site over 17 years are described. Over time, software/hardware improvements have increased the system robustness, leading to a successful 10 Hz data-collection rate of better than 99.98 %. We also provide philosophical concepts that shaped our data system design and are applicable to many different types of environmental data collection.