Comparative Analysis

water temperature, wind direction, wind speed and gust

from Buoy Stations Sandy Hook New Jersey and the

Battery New York in Hudson River

EAS 31136 (Fall 2015)

Professor: Z. Johnny Luo

Cecilia Jancso

Wathanmue Chai

Motivation :Water temperature has big effects on stream ecology since

cold water can hold more oxygen than warm water. Temperature also

influences the rate of photosynthesis by algae and aquatic plants. Some

plants and animals will grow quickly during the warm water in summer. If

water temperatures drop they will grow very slow.

Goal : To analyze relation between water temperature, wind direction,

wind speed and wind gust with Mean, Histogram, Boxplot, Comparing

Two different Datasets, and Hypothesis Testing .

Mean Value

• mean(swt_09) = water temp mean for Sandy Hook at 2009

14.1873

• mean(bwt_09) = water temp mean for Battery at 2009 14.9200

Histograms

water temperature at sandy Hook, New

Jersey in 2009 and 2014 are right skewed

which infers that the mean is greater than

the median.

water temperature at the Battery New York in

the 2009 and 2014 graphs show a random

distribution in the histogram with no apparent

pattern.

Boxplot: Boxplots are used to better understand how values are spaced out in different

sets of data.

The Battery, New York 2009 water temperature median

value is about 15. Graph is skew since there is more

temperature values less than 15 and the bottom of

whisker is longer than top one. Maximum temperature is

greater than 25 and minimum temperatures is lower than

5. In 2014 the median value is about 12 and maximum

temperature is 24 and minimum temperature is 0.

It is shown that the median value of water temperature at Sandy Hook New Jersey in 2009 and 2014 boxplot graph and the median value are about 10. Both graphs are skew since there are more temperature values greater than 10 since the top whisker is longer than bottom one. The maximum temperature is greater than 25 and minimum temperature is 0.

Covariance: Comparing Two different Datasets

Covariance is a measure of how much two variables change together and to study the

relation between variables. Covariance method is used to determine water temperatures of

Sandy Hook New Jersey and Battery New York in 2009 and 2014 are related in any way for

this precise period. In the matlab program we assigned water temperatures of Sandy Hook

New Jersey (swt) and Battery New York (bwt). corrcoef(swt_09, bwt_09)ans = 1.0000 0.8886 0.8886 1.0000

If the covariance is closer to 1 the variables have strong correlation , covariance 0.5-0.8 is

Medium correlation. Weak relationship is when the value is close to 0. Since the correlation

value is close to 1, there is a positive relation between the Sandy Hook and Battery Park

water temperature data.

Hypothesis testing: two-sample t-test

• Test the null hypothesis that the two data samples are from

populations with equal means.

• Are the mean sea water temperatures for the year 2009 are the

same at the buoys in Sandy Hook and the Battery?

Chi square test

• Gaussian distribution: . μ= 14.92 C and σ=7.2523

Simple Linear Regression between wind direction and wind speed Sandy Hook Wind Direction and Wind Speed 2009

Multiple Linear RegressionSandy Hook Wind Direction and Wind Speed, and Wind Gust 2009

References

1. http://www.ndbc.noaa.gov/maps/New_York.shtml

2. http://www.cs.otago.ac.nz/cosc453/student_tutorials/principal_components.pdf

3. Historical data from year 2009 and 2014 from Buoy Sandy Hook, NJ Station

SDHN4 - 8531680 - Sandy Hook, NJ,

http://www.ndbc.noaa.gov/station_page.php?station=sdhn4

4. Historical data from year 2009 and 2014 from Buoy The Battery, NY Station

BATN6 - 8518750 - The Battery, NY

http://www.ndbc.noaa.gov/station_page.php?station=batn6

THANK YOU