The National Research Council (NRC 1999) recommended that the
following ten climate monitoring principles, proposed by Thomas Karl et al. (NCDC, 1995), should be
applied to climate monitoring systems:
- Management of Network Change: Assess how and the extent to which
a proposed change could influence the existing and future climatology
obtainable from the system, particularly with respect to climate variability
and change. Changes in observing times will adversely affect time series.
Without adequate transfer functions, spatial changes and spatially dependent
changes will adversely affect the mapping of climatic elements.
- Parallel Testing: Operate the old system simultaneously with the
replacement system over a sufficiently long time period to observe the
behavior of the two systems over the full range of variation of the climate
variable observed. This testing should allow the derivation of a transfer
function to convert between climatic data taken before and after the change.
When the observing system is of sufficient scope and importance, the results
of parallel testing should be documented in peer-reviewed literature.
- Meta Data: Fully document each observing system and its operating
procedures. This is particularly important immediately prior to and
following any contemplated change. Relevant information includes:
instruments, instrument sampling time, calibration, validation, station
location, exposure, local environmental conditions, and other platform
specifics that could influence the data history. The recording should be a
mandatory part of the observing routine and should be archived with the
original data. Algorithms used to process observations need proper
documentation. Documentation of changes and improvements in the algorithms
should be carried along with the data throughout the data archiving process.
- Data Quality and Continuity: Assess data quality and homogeneity
as a part of routine operating procedures. This assessment should focus on
the requirements for measuring climate variability and change, including
routine evaluation of the long-term, high-resolution data capable of
revealing and documenting important extreme weather events.
- Integrated Environmental Assessment: Anticipate the use of data
in the development of environmental assessments, particularly those
pertaining to climate variability and change, as a part of a climate
observing system’s strategic plan. National climate assessments and
international assessments (e.g., international ozone or IPCC) are critical
to evaluating and maintaining overall consistency of climate data sets. A
system’s participation in an integrated environmental monitoring program can
also be quite beneficial for maintaining climate relevancy. Time series of
data achieve value only with regular scientific analysis.
- Historical Significance: Maintain operation of observing systems
that have provided homogeneous data sets over a period of many decades to a
century or more. A list of protected sites within each major observing
system should be developed, based on their prioritized contribution to
documenting the long-term climate record.
- Complementary Data: Give the highest priority in the design and
implementation of new sites or instrumentation within an observing system to
data-poor regions, poorly observed variables, regions sensitive to change,
and key measurements with inadequate temporal resolution. Data sets archived
in non-electronic format should be converted for efficient electronic
- Climate Requirements: Give network designers, operators, and
instrument engineers climate monitoring requirements at the outset of
network design. Instruments must have adequate accuracy with biases
sufficiently small to resolve climate variations and changes of primary
interest. Modeling and theoretical studies must identify spatial and
temporal resolution requirements.
- Continuity of Purpose: Maintain a stable, long-term commitment to
these observations, and develop a clear transition plan from serving
research needs to serving operational purposes.
- Data and Meta Data Access: Develop data management systems that
facilitate access, use, and interpretation of data and data products by
users. Freedom of access, low cost mechanisms that facilitate use
(directories, catalogs, browse capabilities, availability of meta data on
station histories, algorithm accessibility and documentation, etc.), and
quality control should be an integral part of data management. International
cooperation is critical for successful data management.
Karl, T.R., V.E. Derr, D.R. Easterling, C.K. Folland, D.J. Hoffman, S. Levitus,
N.Nicholls, D.E. Parker, and G.W. Withee, 1995: Critical issues for long-term
climate monitoring. Climatic Change, 31, 185-221.
National Research Council (NRC), 1999:
Adequacy of Climate Observing Systems, National Academy Press,