zzzGretaLeber-MatlabResults

=Basic parts:=

1. Download and read...
My language code file for making the below figures is linked. I started from scratch.

===2. Calculate zonally averaged P and v over longitude, and plot the resulting latitude-time series.===

Here is the latitude-time sections of P and v in the zonal mean, and at 90W:  Note that the x-axis labels are months, rather than numbers. The code to do this is: set(gca,'XTick',1:1:12) set(gca,'XTickLabel',{'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'})

Also, to plot the figures next to each other, use code: subplot(1,2,1) %followed by code to plot first figure and then prior to second figure use: subplot(1,2,2)

Both figures on the right reveal that 90W ("our latitude") is typical in its overall spatial patterns of vwnd and precipitation but that the magnitude of both differ from the mean. In particular, the magnitude of both the vwnd and precipitation is much higher at 90W. This may not be immediately apparent since the colorbar limits are different between the right and left figures. Changing the colorbar axis to be identical right to left reveals the much larger precipitation and vwnd magnitudes at 90W:  To change the colobar axis, one must simply specify the range for the colorbar using command caxis. For top figures, use: caxis([0 14]) %and for bottom figure, use: caxis([1 6])

Both vwnd and precipitation are larger near the equator at 90W, while vwnd at 90W also shows a measurable increase over the mean over the southern ocean. ===3. Average air temperature over both lat and lon, to make a 12-month time series. Which season has the warmest global mean surface temperature? Can you understand why?===

Global mean surface temperature has a mild annual cycle: Its sense is consistent with the idea that the heat capacity of air is less than that of water. Since this is air temperature, its maximum correlates to the period of maximum incoming solar radiation, eg summer. If this were a time series of sea surface temperature, its maximum would occur during autumn due to water's higher heat capacity.

===4. Make a map of the temporal (i.e. seasonal) standard deviation of precipitation, expressed as a percentage of the annual mean precipitation. This might be one definition of a "monsoonal" climate.===

Here is a map expressing the seasonality of precipitation: 

Or, if you prefer a different projection: Once one has dowloaded the m_map toolbox located [|here], it is very easy to change the projection. For the top figure, one sets: m_proj('Miller Cylindrical','lat',[-90 90],'lon',[0 360]) %and for the bottom: m_proj('Robinson','lat',[-90 90],'lon',[0 360])

Places with intensely seasonal rainfall tend to be those areas that experience monsoonal climates, generally speaking in areas just north and south of the equator. The two areas of highest variability are those associated with ENSO (Eastern Pacific) and African Monsoon (Northern Africa).

5. What is the space-time standard deviation of 'air' (temperature)?
The total space-time standard deviation of temperature is 15.22. The challenge of computing it is that we want area averages over the Earth, but we started with lat-lon grids. A simple call of stdev(air array) gives a value of 27.78 which is too large since it essentially "weights" values at the pole too much. Variability at the poles is much greater than other areas of the globe since their seasons are exaggerated.