CALCULATING CLIMATE FROM ANALOGS


The output file from the NAPD run "napd.out" contains meta data of the location and publication for each modern analog. If the meta data for each analog (MOD5_0454, MOD5_1660, etc.) included contemporary climate values, they could be used to estimate past climate for fossil samples. (The last two variables of the CLIMAP meta data are Sea Surface Temperatures)



The file SURFWUS.TXT contains 1363 contemporary pollen samples from Western North America (Davis, 1995). The samples from tropical Mexico have been removed from the file linked to below, and the variable names have been changed to match NAPD 70 protocol. (You still should check the names for constancy, however.)
File SURFMETA.TXT contains the meta data for SURFWUS.TXT including mean annual temperature (oC) and average precipitation (mm) for each analog. File SURFRULE.TXT converts the counts to proportions. File SURFRUN.TXT is the Run Description. Create a new subdirectory named "surf" and download these four text files by opening them with your browser, and then using the browser's "save as" function to save them to the "surf" subdirectory.
SURFWUS.TXT
SURFMETA.TXT
SURFRULE.TXT
SURFRUN.TXT



Download the "Tilia 2.0 File" for "Montezuma Well" from the NGDC site and save it in the "surf" directory as "montezuma.txt". Change the first line of "montezuma.txt" from
# GPD ASCII Format
to
# NAPD ASCII Format
Before saving "montezuma.txt", open "surfwus.txt" using another instance of WORDPAD, or NOTEPAD, and change any names (in "montezuma.txt") that do not match (for example, Chenopodiaceae). Save "montezuma.txt" and save or just close "surfwus.txt".



Copy "analog.exe" and "napdrule.txt" from the "napd" subdirectory to the "surf" subdirectory, which should now contain the files:
analog.exe
montezuma.txt
napdrule.txt
surfmeta.txt
surfrule.txt
surfrun.txt
surfwus.txt



Open a DOS window, move to the "surf" subdirectory, and run the ANALOG program by typing at the DOS prompt
analog surfrun.txt




Open the file "surface.out" with WORDPAD. The first 10 rows
(for the Montezuma Well sample at 0 cm) should look like this
Sample ID	Rank	Analog ID	Distance	Analog	Latt	Longit	pCm	tCA	ElvM	Vegt
0, , 0	0	CJHE22	0.010060	CJHE22	46.95	121.77	1042	12	530		NWXF
0, , 0	1	ARCH18	0.019261	ARCH18	34.00	118.00	350		19	69		CAST
0, , 0	2	CJHE18	0.021047	CJHE18	46.95	121.77	1282	10	820		NWMF
0, , 0	3	WORE16	0.042908	WORE16	44.50	123.50	928		13	311		NWMF
0, , 0	4	WORE15	0.048011	WORE15	44.50	123.50	833		13	333		NWMF
0, , 0	5	ARCH14	0.048661	ARCH14	37.00	119.00	360		19	205		CAST
0, , 0	6	CJHE14	0.059942	CJHE14	46.95	121.77	1497	8	1175	NWMF
0, , 0	7	CJHE16	0.064078	CJHE16	46.95	121.77	1427	9	1060	NWMF
0, , 0	8	CJHE24	0.066871	CJHE24	46.95	121.77	935		13	295		NWXF
0, , 0	9	WORE08	0.069000	WORE08	44.50	123.50	956		12	355		NWMF




All of the dissimilarity values are low. What is the average temperature for the 10 analogs? (12 + 19 + 10 .... /10 = 12.8 oC) the average precipitation is 961.0 mm. Other statistics, such as standard deviation, can be calculated for the climate analogs. Because this is a tab-delimited file, you can cut and paste it into EXCEL to simplify these calculations.

For this (ANALOG) exercise, print out the analogs for the first five samples with the average Temperature and Precipitation calculated for each sample.

Hand these in.

Next



Davis, O.K. 1995.
Climate and vegetation patterns in surface samples from arid western U.S.A.: Application to Holocene climatic reconstructions. Palynology. 19:97-120.