1. Observing Climate Variability and Change
Thomas R. Karl
National Oceanic and Atmospheric Administration
National Environmental Satellite Data and Information Service
National Climatic Data Center
Asheville, NC , USA

2. } } $ $ PHYSICAL PROCESS BIOLOGICAL PROCESSES CLIMATE CHANGE FORCINGS
1) How has the climate changed or varied?
PHYSICAL
PROCESS
2) How well do we understand the climate system ?
3) What are the causes of climate change and variability?
4) How can we characterize the impacts of climate change?
BIOLOGICAL
PROCESSES
CLIMATE CHANGE FORCINGS
IMPACTS
CROP
YIELD } } $ $
COASTAL
HABITAT
FOREST MIGRATION

5. How significant are the uncertainties?
State and Forcings Variables
Few have quantitative confidence intervals (CIs) (including time- dependent biases) e.g., global surface temperature, CO2
Most CIs do not include time-dependent biases
For many, CIs are uncertain or unknown
Why?
Adhering to climate observing principles and guidelines still does not have a high priority
Viewgraph 1. Effect of Diurnal Correction on the MSU Channel 2 Time Series.
Over the lifetime of each NOAA satellite, the orbital parameters change in such a way that the local equatorial crossing time (LECT) drifts. In some cases, most noticeably NOAA-11, this drift can be more than six hours. The drift in LECT leads to a corresponding drift in local observing time that can cause any diurnal signal to be aliased into the long-term time series. In this viewgraph, we plot the LECT for each platform (top plot), and two global MSU channel 2 time series, averaged over latitudes from 50S to 50N, with an without the correction for drifts in diurnal sampling(bottom plot). The blue curve is the uncorrected time series, and the red curve is the time series with the aliased diurnal cycle removed. Also in the bottom plot, we show the difference between these two time series on an expanded vertical scale.
Smoothed annual anomalies of global combined land-surface air and sea surface temperatures (oC).

6. The Climate Observing System: What is needed?
Adoption of ten principles for climate monitoring
More comprehensive global observations --- Prioritization concept
Improved global telecommunications
Better use of data… more products
Critical need for system monitoring and oversight responsibility --- Examples

7. The Climate Observing System: What is needed?
Adherence to Ten Principles for both space- and surface-based observations
1. Management of Network Change
2. Parallel Testing
3. Metadata
4. Data Quality and Continuity
5. Environmental Assessments
The international framework for sharing data is vital.
6. Historical Significance
7. Complementary Data
8. Climate Requirements
9. Continuity of Purpose
10. Data and Metadata Access

8. Definition of Terms Impact – potential for reducing uncertainties
Time to Pay-Off – the time required for an impact to be realized, i.e., upgrading an existing system or implementing a new system
Feasibility – readiness to implement the observing system considering technical aspects and resource requirements

9. Example: Demonstrating Prioritization Concept
A Global Network of Reference Quality Radiosonde Sites

10. Temperature Indicators “Climate Impacts”

11. Temperature Indicators “Climate Understanding”

12. Hydrological Indicators “Climate Impacts”

13. Hydrologic Indicators “Climate Understanding”

14. What are the causes of climate change and variability

15. The Climate Observing System: What is needed?
Observing Systems Oversight and System Monitoring Capability
Establish climate requirements for observing systems (atmosphere, ocean, terrestrial, cryosphere), such as weather services do today
Includes instruments on satellites
Spatial and temporal sampling, etc.
Reprocessing and reanalysis
Tracks the performance of the observations, the gathering of the data, and the processing systems
Resources and influence to fix problems

16. Real-time Network Performance Monitoring
U.S. Climate Reference Network

19. Observing and Data System Deficiencies
Five different research teams using independent methods to identify time- dependent biases in the tropospheric temperature records
Teams: NOAA – GFDL – NCDC Univ. of Alabama UK Meteorological Office Texas A & M University)
Percent of Teams Identifying Biases
Courtesy: Free et al (in review BAMS)

20. The Climate Observing System: What is needed?
Adoption of ten principles for climate monitoring
More comprehensive global observations
Improved global telecommunications
Better use of data… more products
Critical need for system monitoring and oversight responsibility

21. Some Variables are Effectively Monitored for Trend
Scripps Institute of Oceanography
NOAA

22. Observing and Data System Deficiencies
Impact of Satellite Orbital Drift
Will be fixed on US NPOESS (2009)
Changes in orbits and equator crossing times of satellites are aliased onto the diurnal cycle, requiring corrections
Ascending minus descending temperatures MSU2 JJA from NOAA 11
MSU channel 2 temperatures over land, from Wentz (black lower)
and Christy-Spencer (red lower) and difference (top).
Diurnal corrections required for each satellite.

23. Observing and Data System Deficiencies
Courtesy F. Wentz
Effect of Calibration Target Correction on MSU Channel 2