This project uses GLOBE data: GLOBE Task Team and others (Hastings, David A., Paula K. Dunbar, Gerald M. Elphingstone, Mark Bootz, Hiroshi Murakami, Hiroshi Maruyama, Hiroshi Masaharu, Peter Holland, John Payne, Nevin A. Bryant, Thomas L. Logan, J.-P. Muller, Gunter Schreier, and John S. MacDonald), eds., 1999. The Global Land One-kilometer Base Elevation (GLOBE) Digital Elevation Model, Version 1.0. National Oceanic and Atmospheric Administration, National Geophysical Data Center, 325 Broadway, Boulder, Colorado 80305-3328, U.S.A. Digital data base on the World Wide Web (URL: http://www.ngdc.noaa.gov/mgg/topo/globe.html) and CD-ROMs.
https://www.ngdc.noaa.gov/mgg/topo/globe.html
https://www.ngdc.noaa.gov/mgg/topo/report/globedocumentationmanual.pdf

Elevation Code: elevations.py

This analysis counts tropical storms and hurricanes and corrects for linear trends in tropical storm and hurricane detection. Of course the detection of tropical storms and hurricanes has not changed linearly, but 100 years of near-land storm detection shows about a 7% increase to a 23% decrease in the percent of storms near land. Using the linear correction is probably adequate for the oldest data and some newer data as satellite-based detection is still improving.

The storms near land (versus storms not near land) should be constant. There's no physical reason for storm tracks to change from nearing land to not nearing land over the past 100 years. But there is a reasonable likelihood that storms near land were easier to detect 100 years ago, whereas storms over the open ocean are now equally easy to detect.

However, the change is different for different storm strengths:

Min speed (knots)	Max speed (knots)	Trend per year
35	54	-0.00230
55	69	0.000785
70	84	-0.00209
85	104	-0.001615
105	124	-0.001824
125	and up	-0.001067

The counts in each category for the year is adjusted by multiplying by (1 - (trend * (YEARS[1] - current_year)))

The corrected counts show a large increase in the strongest hurricanes (>= 125 knots). There's an increase in stronger tropical storms, some increase in weaker tropical storms. The other hurricane counts are flat.

Code: tropicalnumbers.py | Data: hurdat.csv | Instructions: README