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 28801-5001, USA

} } $ $ 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

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).

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

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

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

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

Temperature Indicators “Climate Impacts”

Temperature Indicators “Climate Understanding”

Hydrological Indicators “Climate Impacts”

Hydrologic Indicators “Climate Understanding”

What are the causes of climate change and variability

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

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

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)

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

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

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 1989-91 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.

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