EdGCM Lab 3: Investigating How Ice Melt Will Drive Sea Level Rise [ADD YOUR COURSES DETAILS HERE]

Continuing to learn to make maps (20 min) Agenda Review of Models (10 min) Continuing to learn to make maps (20 min)

Review of Models As we now know, the global climate is generally in equilibrium on human time scales (even though some factors influencing it are episodic) When the climate is out of equilibrium, negative and positive feedbacks swing it back to balance. Feedbacks usually lag behind at a slower pace. The amount of incoming solar radiation is balanced by the amount of outgoing terrestrial radiation (section 1.2.3), so that the Earth neither continues indefinitely to heat up nor cool down. GCMs simulate not only feedbacks, but the lag in their impact…

Review of Models We can investigate when a model comes into equilibrium by creating a time-series graph in Excel We can even compare equilibrium between different scenarios by plotting them together on a time-series graph

Review of Models Modern models account for feedbacks in the climate system Source: NOAA, 2010

Review of Models The GCM produces raw data files of various diagnostic quantities that have been calculated by the physical equations in the model Data files must be post-processed so that usable information can be extracted more readily Diagnostic variables are visualized and analyzed to check the model accuracy as well as the outcome of the climate experiment GCMs are computer programs, mostly written in Fortran and requiring a fairly high level of programming skills to operate, let alone develop

How Good Are GCMs, Anyway? No model is perfect – all have limitations (including sea level rise not being included) Certain aspects reflect uncertainty in current knowledge (clouds, sea ice) Accurately reproduced past climates (confirmed by records), predicted modern climate effects (mt. pinatuba)…but still have limitations… -won’t tell you when it will rain -how local can you go? -some simulated features are rudimentary Still, numerical climate models as representations of the Earth system do a very good job of helping us understand past, present and future climates

Review of Models In part because we calibrate them using hindcasting and current conditions To ensure that they are accurate when we run them into the future to consider possible future scenarios….

Continuing to Make Maps and Manipulate Them for Better Accuracy

Visualizing Output on a Map… Let’s take 10 minutes to make sure we can all do this…I’ll show you first… Why is it important to manipulate the range? What about the color bar? Are there cases where we might want to adjust having continents or oceans filled? How do you make an anomoly map? (What is an anomoly map?)

Should We Interpolate Our Maps? Interpolation = “Allows the model to estimate values of data between two known values.” Does it look different?

What Happens if We Use a Different Map Projection? Try a Mollweide map. What happens? It accurately portrays area but distorts shape and direction… If we want to see the poles, should we try a polar projection instead?

Now We Need a Control Right? Let’s extract the same variable data for the “Modern_Predicted SST” scenario. Again, let’s only use the last five years. Make sure you choose the same variables and the same geographic range/time range. Now let’s finalize this map (map type, scale, color bar, continents).

Questions to Ask About Our Maps Where do we see the greatest loss of land ice? Can we quantify this loss with the scale? Or using the grid? Let’s compare our two maps. What differences do we see?

Can We Further Compare our Maps? Do you remember the steps to create an anomoly map? Let’s try it with the set of the maps we just created… Now let’s finalize the map (map type, scale, color bar, continents)

Questions to Ask About Our Anomoly Map Is it easier to now see where the greatest loss of ice occurs? How much will the increase or decrease be? How does this trend compare with what’s seen by satellites and reported at the National Snow and Ice Data Center? Use Google to find their data and reports. Oceans absorb heat and act as a cooling system…

EdGCM Free Exploration Now that you know how to make time series graphs and global maps, you might try: Others of the scenarios with the same steps. Different variables you are interested in. Manipulating forcings and setting up your own scenario. Make sure you adjust all the settings on your map to be optimum for whatever situation or variable(s) you are investigating.