The Basic Research Model Models/Theory NWP GCM/CSMs Process Mods. Observations Soundings Satellites Surface Obs. Predictions Boundary Conditions Initial Conditions Better data result in better model predictions Better model physcis/numerics also result in better model predictions Comparison of model-observation differences shows where improvements are needed

An Example: NWP Skill 5-day NH forecasts today are as good as 1980’s 3-day forecasts 7-day SH forecasts today are as good as 1980’s 3-day forecasts in SH Convergence of NH and SH skills reveal two things: better models & incorporation of satellite data. Wallace + Hobbs, Fig % skill means the model perfectly predicts the flow field at ~5 km. Model Improvements: -Higher Resolutions -New, better physical parameterizations Observational Improvements: -Satellites (winds, sounders, etc.) -Aircraft Soundings -More surface sounders

Initial Conditions for NWP Models There is an increasing need for new and sophisticated satellite and surface observing technologies

Forecasting: Interesting Directions Now-casting: Using Synoptic Conditions to Predict Extreme Hazards

Forecasting: Interesting Directions Forecasting Fire Hazards: Requires detailed understanding of surface biology in addition to weather

Forecasting: Interesting Directions Hurricane Forecasting: Predicting Hurricane Formation Frequency, Track, and Intensity Involves both Seasonal and Synoptic Forecasting Efforts

Forecasting: Interesting Directions There are increasing efforts to rely on national energy resources Solar energy and Wind are attractive renewable energy sources These place new demands on synoptic and climatological forecasting efforts.

Atmospheric Chemistry: Aerosols Aerosols are particles suspended in the atmosphere, ranging in size from nanometers to micrometers We associate them with smoke, smog, and dust storms, but they actually play a number of very important roles: Reductions in visibility (“Haze”) and surface solar energy Air Quality reduction – a vector for toxins and a source of allergies Source of “cloud condensation nuclei” – the seeds upon which every cloud drop forms As with CO 2, aerosol concentrations are increasing in time due to anthropogenic activities (biomass burning, SO 2 emissions from coal fired power plants, condensation of organic vapors from cars and industry, fertilizers, dust, etc.) Unlike CO 2, aerosols tend to cool the surface. Aerosol effects are the largest source of uncertainty in long-term estimates of man’s impact on climate.

Atmospheric Chemistry: Ozone Reductions in Global Ozone Concentration related to emissions of CFCs, a common refrigerant Montreal Protocol & its amendments enacted a global elimination of the use/production of CFCs CFCs and other processes contribute to the annual SH springtime Ozone Hole 1 st observations of Ozone hole viewed as a “mistake” by NASA when interpreting data Ozone is an essential component of the stratosphere, reducing harmful UV rays at the surface. It is also a toxin in the troposphere, caused by emissions of NO x and VOCs (Volatile Organic Carbon species).

Atmospheric Chemistry: CO 2 CO 2 is increasing globally due to use of coal and oil. Used as the “poster child” example (along with ozone) of humankind’s ability to impact the global atmosphere. There is strong evidence that increases in CO 2 and other greenhouse gases are responsible for the underling global average warming trend over the past 120 years. Increases in CO 2 also acidify the oceans, affecting marine life Paleoclimate studies show that CO 2 and perhaps CH 4 (methane) have amplified the effects of previous climate shifts

Climate Dynamics: Global Change

Climate Dynamics: Radiative Forcing Changes in the atmosphere and surface can change the heat absorbed and emitted by the planet. Changes may occur in the solar spectrum – Earth’s heat source – or the infrared – the return branch of the energy stream. “Tweaks” in either stream are called “radiative forcings” of the climate system. CO 2 reduces the outgoing stream, aerosols reduce the incoming stream.

The Coupled Climate System Forcings of the Radiation budget are just a start…. The responses of the climate system are extremely complex. Studies of climate change thus involve efforts from virtually every discipline in the atmospheric sciences.