Comparison of NEXRAD Precipitation Data to
Measured Levelogger Data
Data for this project came from
3 very helpful entities, AMAFCA, NOAA, and the United States Geologic Survey
(USGS). AMAFCA has a wide variety of data available for public use, and a great
asset for a lot of data for this project. The dates of storms were chosen from
the criterion of differing in size as well as falling over the North and South
Pino watersheds. From these dates, levelogger
discharge rates were recorded from AMAFCA records, the quantitative numbers are
shown in the blue, or the top chart in the image below. The National Climate
Environmental Information (NCEI), provided the information for NEXRAD. Here
Level-III data, the processed data, was downloaded in the formats of total
rainfall accumulation, reflectivity and one- hour precipitation. Other products
off of this site include three-hour precipitation, reflectivity (short and long
range), velocity, the melting layer, hail index and many others. NOAA’s weather climate toolkit (wct) was used for animation of storms from the total rain
fall as well as the reflectivity and used to convert the NEXRAD data to a
format that ArcMap could read. Finally, the last source of data came from the
USGS where land cover patterns for the specific watersheds were downloaded.
All AMAFCA data is projected
using ‘NAD
1983 State Plane New Mexico Central FIPS 3002’and geographical coordinates of
GCS North American 1983, so these were implemented for the rest of the project
data. The projection of the State Plane is a Transverse
Mercator with a Central Meridian of -106.25 and finally a Linear Unit of
Meters. Upon further analysis, state plane projections are used to map areas
with a high level of accuracy. Each state within the US is broken up into its
own range of state plane coordinate systems (SPCS), New Mexico has 3. With
changing the central meridian of the projection to be 106.25, this places the
region of centralization right over the 
Albuquerque Metropolitan
area.
To be able to analyze the precipitation data, it must first be
converted into a runoff value. To do this the rational method was used. The
rational method consists of a discharge being a multiple of a land cover, area and intensity (
). The intensity of these two rain storms were
found by gathering a total rainfall accumulation and dividing it by the time of
storm concentration with units of (inches/hour). The land cover values, as well
as the c multiples are shown. Applying these two factors to the areas of the
North and South Pino, in units of acres, allowed a discharge to be calculated.
