Geog477 – Lab 7Due: December 10, 2007

Lab 7: Term Project - Part III

Regional Analysis – Report Writing

Drought Impacts in the Mid-Atlantic del Sur (Virginia, North Carolina, South Carolina)

At this point you should have your introductions finalized as well as your methods. This lab you should focus on the additional analyses that we discussed in class Tuesday, November 27th. You should be working out the methods with your group members and writing up a report on your own. Please read over the Lab4_drought_gradingNotes.doc under Data\TermProject and make sure you are following the recommendations I made at the end of the document.

Everyone should be doing some region-wide analysis. In the last lab we created a time-series of NDVI observations to examine the dynamics of the growing season and to monitor the drought-impacts on primary production. We calculated the region’s average cumulative ‘greenness’ over an 8-year period. Since the goal was to identify those years which differ substantially from the average year for our study region it would make sense to go ahead and create a difference map for each year. Remember to use the mean as the ‘after’ image. Focus on drawing some conclusions from the most compelling difference maps. There is often a time-lag in ecosystem responses to stress as measured by vegetative productivity. Think about the results you might expect to see in NDVI differences in consecutive drought years as opposed to a drought year following a year of above-average precipitation. Think about why you were seeing the increase in productivity near the coastlines during drought years – remember LakePowell. Try to summarize your results numerically – remember how to get the mean, standard deviation, etc. for the entire image? Do this for the difference map – not the highlight change.

We discussed breaking up the analysis into four different approaches; landcover, ecoregions, climate divisions and region wide. A useful tool for many of you will be the zonal attributes tool under GIS Analysis in the Image Interpreter. This allows you to summarize the pixel values for specified areas – in our case the ecoregions and climate divisions. You will likely have to export a lot of your data to excel to make the graphs and tables necessary for this analysis.

Landcover

You might want to create some masks of landcover data using the 1km MODIS landcover data and focus your analyses on particular landcover classes. Use the IGBP classification scheme.

Your goal is create a summary table that has the mean and standard deviation of NDVI for each year (2000, 2001, etc.) for each land cover class you examine; urban, mixed hardwood/deciduous, agriculture, evergreen, wetlands, etc.

Ecoregions

Get familiar with the ecoregions shapefile. There are two hierarchies of regions you should be looking at Class 3 and 4. You should summarize the effects of the drought for all ecoregions in class 3 visually. Create the graph that Aaron drew on the board for NDVI accumulations by ecoregion through the season. I have copied the ecoregion shapefile into the term project data folder, and it is named ncscva_level4_UTM.shp but the shapes for level 3 are also stored in this data file. You should display

Climate Divisions

You should be reporting the average NDVI for each year by climate division and try to discern which regions were impacted more severely by the drought. Try to create the graph that Aaron described with the precipitation anomalies on the x-axis and the mean difference in NDVI on the y-axis and the climate divisions values plotted.

Region-wide Analysis

Your analysis will be on the entire region. You should aim to create the graph with cumulative NDVI on the y-axis and the accumulated NDVI through the growing season on the x-axis. You should plot the 13 values for each year and plot the average for the entire 8-year period. You should also be working with some climate data, either precipitation anomalies or percent of normal.

For everyone, back up your analysis with climate data. Some sites you might want to check out:

  • Precipitation anomalies are percent of normal precipitation for the region would help to interpret your results. Go to the ClimatePredictionCenter
  • US Drought Monitor – has drought monitor data as well as the Palmer Drought Severity Index (PDSI)
  • is a newest, latest greatest tool from NOAA. Allows download of shapefiles – though the archive does not go back very far.

I will be available Tuesday and Thursday 11-1 in Saunders 319 until the project is due, December 10th, 5:00 p.m. You can also reach me by email and we set up a time to meet as needed.