Jennifer Brown

Lisa Owen

POSTER PRESENTATION

April 30, 2004

# Investigation Question:

In the United states are summers more humid on the east or west coast?
Also, comparing northern and southern locations, which has the highest
relative humidity? What factors contribute to the difference in humidity
levels?

# Hypothesis:

We believe that the east coast will have higher average humidity levels
than the west coast. This may be caused by the location of the school.
The Atlantic Ocean and the Gulf of Mexico affect the humidity levels of
the east coast. Also, we predict that the school to the South will have
a higher humidity than the northern school. This difference may be a
factor of elevation.

**[Background:]{.underline}**

[Relative Humidity]{.underline}- The amount of water vapor in the air at
any given time. It is usually less than that required to saturate the
air. The relative humidity is the percent of saturation humidity,
generally calculated in relation to saturated vapor density.

Relative humidity is a ratio, usually expressed as a percentage that is
dependent upon the temperature; these two factors should be considered
together.

Relative humidity or atmospheric moisture, controls potential
evapotranspiration rate from soils and vegetation surfaces. An increase
in the intensity of the hydrological cycle predicted from GCM
simulations of future climate would both increase relative humidity, and
be modified by concomitant changes in atmospheric moisture. Because of
its role in the linkage between vegetation and atmosphere (the end
result of soil moisture being transported within and evapotranspired
from vegetation surfaces), relative humidity is both a climate change
forcing function, and a response variable. This provides it with a
central importance in climate change.

**[Procedure:]{.underline}**

Two sets of schools are compared in this investigation. One set contains
schools from the east and west coast that have similar latitudes. The
other set of schools comes from the north and south and have relatively
similar longitudes. The schools that were selected for this
investigation were Montgomery Middle School in San Diego, California
(west), Pine Crest Lower School in Fort Lauderdale, Florida (east),
Tabor Academy in Marion Massachusetts (south), and Hartland Consolidated
School in Hartland Main (north).

To obtain the best information it is best to begin collecting data from
the graphing section of the GLOBE search engine. In order to be useful
for the investigation the schools must have at least twenty data sets
for each of the summer months being compared. Also, to ensure accurate
results the humidity readings must be taken using and sling hydrometer
and the temperature taken by a standard or digital thermometer. One the
relative humidity and temperature data is organized in the table format;
averages must be taken for each of the summer months (June -- August).
The summer that is being compared for this investigation was the summer
of 2002.

After both temperature and relative humidity are averaged for all four
locations for all three months, the comparisons of north to south and
east to west can be done. When comparing the data it is important to
consider what outside factors have an effect on the temperature to
humidity ratios.

**[Error Analysis:]{.underline}**

There are many variables that must be considered with this experiment.
Although the two sets of schools have similar latitudes and longitudes
they have different overall global positioning. How close a school may
be to a body of water is a major factor that controls the amount of
moisture in the air in that particular location. Also the elevation of
the school may also have an effect on humidity. And lastly, the average
monthly rainfall in an area can have a major effect on the monthly
humidity averaging process. A rainy day is a 100% humidity reading. Too
many 100% can through off humidity levels. Taking the rainy days out of
the equation may help to create better results.

**[Present status:]{.underline}**

Relative humidity measurement sites are erratically and sparsely
distributed, mostly at airports and research stations. This network is
entirely inadequate for modeling effects on the atmosphere, vegetation,
and hydrology, especially mountainous terrain.

Graphs:

+-----------+--------+--------+--------+--------+--------+--------+
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**[Key]{.underline}** (for above graphs):

1: Montgomery Middle School, San Diego CA

2: Pine Crest Lower School, Fort Lauderdale FL

3: Tabor Academy, Marion MA

4: Hartland Consolidated School, Hartland ME

  -------------- -------- -------- -------- -------- -------- -------- --------
  Summer of 2002                            June (%) July (%) Aug. (%) Avg. (%)
  Relative                                                             
  Humidity                                                             

                                                                       

  Montgomery                                30       26       24       26.6
  Middle School,                                                       
  CA                                                                   

  Pine Crest                                64       62       53       59.6
  Lower School,                                                        
  FL                                                                   

  Tabor Academy,                            74.48    68.92    72.48    71.96
  MA                                                                   

  Hartland                                  55.63    57.63    43.06    52.12
  Consolidated                                                         
  School, ME                                                           
  -------------- -------- -------- -------- -------- -------- -------- --------

  -------------- -------- -------- -------- -------- -------- -------- --------
  Summer of 2002                            June     July     Aug.     Avg.
  Temperature ©                                                        

                                                                       

  Montgomery                                29       30.5     33       30.8
  Middle School,                                                       
  CA                                                                   

  Pine Crest                                32.5     35       37       34.8
  Lower School,                                                        
  FL                                                                   

  Tabor Academy,                            18.2     22.6     22.8     21.2
  MA                                                                   

  Hartland                                  17.2     21.3     22       21.07
  Consolidated                                                         
  School, ME                                                           
  -------------- -------- -------- -------- -------- -------- -------- --------

**[Outcomes:]{.underline}**

After comparing the data of these two sets of schools, the results
support my hypothesis. The south was more humid when compared to the
north and the school from the east had higher relative humidity reading
than the school from the west. The major difference of the northern and
southern comparison was the elevation. The northern school had a much
higher elevation than the southern school. The higher up the air the
thinner it is and the less able it is to hold moisture. This elevation
factor could be the reason for the difference in humidity readings. The
major difference in the east to west comparison was location and average
monthly rainfall. It rained much more in Florida during the summer
months than it did in California. The 100% humidity reading altered the
monthly averages for this comparison. A reason for the increased
precipitation levels in Florida could have been due to the location of
the school. The two major bodies of water the surround the school create
more moisture in the air. Overall the three factors that contributed to
the differences in the relative humidity readings were location,
elevation and precipitation.

**[Sources:]{.underline}**

1)  [http://www.wno.ch?web/gcos/terre/variable/relhum.html]()

2)  <http://www.nedcc.org/plam3/tleaf21.htm>

3)  <http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/relhum.html>