Date post: | 19-Jan-2016 |
Category: |
Documents |
Upload: | hester-washington |
View: | 220 times |
Download: | 0 times |
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