DataStr=
eme
Atmosphere Current Weather Studies 2B:
THE ATMOSPHERE IN THE VERTIC=
AL
Do Now:
- Print this file.
- Print the Wednesday Curre=
nt
Weather Studies Image
1 File.
- When available, answer the
two Concept of the Day questions in the Thursday, 17 September 2009 Da=
ily
Summary File.
To Complete Investigation:
- Read Chapter 2 in the DataStreme Atmosphere textbook and
respond to the Chapter Progress Questions in the DataStreme Atmosphere Study Guide
Investigations binder. [Do not complete the Questions for
Review and Critical Thinking Questions appearing in the =
Weather
Studies Investigations Manual].
- Complete the introductory
portion of Investigation 2B in the Weather Studies Investigations
Manual, which ends when you reach the statement, "As direc=
ted
by your course instructor, complete this investigation by either: ---<=
/b>."
[Do not complete the Applications portion of the Investigation.=
]
- Go to the Wednesday - =
CWS
B (Current Weather Studies B) link on the course website to comple=
te
this investigation.
As we wind down the summer season (fall officially begins next week with=
the
autumnal equinox on 22 September), the country and its overlying atmosphere=
is
responding to the decreasing sunlight due to shorter days and lowering path=
s of
the sun. However as noted in the Wednesday, 16 September, Daily Weather
Summary, the upper atmospheric flow patterns remain weak and summer-like
resulting in slow moving weather systems and abundant thunderstorms across =
the
country. A hint of cooler air has begun teasing the northeastern U.S. bo=
rder
however.
Upper atmosphere data are collected by radiosondes<=
/span>
at 00Z and 12Z each day from about 70 stations across the U.S. as=
part of
a worldwide effort of sensing the three-dimensional atmosphere for weather
analysis and forecasting. The following selected data were obtained by the =
rawinsonde (a radiosonde =
instrument
also tracked for wind information) observation from =
Salem, Oregon
for 00Z 16 September 2009. Plot these temperatures at their respective pres=
sure
levels over Salem<=
/st1:City>
on the Stüve diagram of page 2B-3 of the <=
i>Weather
Studies Investigations Manual that you used in the introductory portion=
of
this activity. The course website provides links for an additional copy of =
the Stüve diagram if necessary. [Note: The pr=
essure
scale is decreasing upward along the left side.] Connect these points
with a dashed line to distinguish from the Standard Atmosphere plot.
|
Pressu=
re (mb)
|
Temper=
ature
(°C)
|
Altitu=
de (m)
|
|
100
|
–65=
.3
|
16580
|
|
150
|
–61=
.3
|
14100
|
|
172
|
–63=
.7
|
13249
|
|
300
|
–35=
.5
|
962=
0
|
|
500
|
=
211;7.9
|
585=
0
|
|
700
|
&nb=
sp; 7.6
|
315=
9
|
|
850
|
15.=
4
|
153=
4
|
|
1008 (surface)
|
27.=
4
|
&nb=
sp; 61
|
1=
. From
the surface to about the 220-mb pressure level, temperatures in the atmosph=
ere
over Salem on
16 September at 00Z were [(warmer)(about
the same as)(colder)] than Standard Atmosphere
conditions.
2=
. The
tropopause is a defined boundary that separates=
the
troposphere where temperatures generally decrease with increasing altitude,
from the stratosphere where temperatures are steady (isothermal) or
nearly so, or they increase with altitude (inversion). Based on the
temperature data you plotted, the tropopause ab=
ove Salem was located=
at a
pressure level of [(500)(=
300)(172)]
mb at 00Z on 16 September 2009.
3=
. The
tropopause over Salem
at this time occurred at [(a lower)(the
same)(a higher)] altitude than in the Standard
Atmosphere. (Recall from the first part of this investigation, the Standard
Atmosphere tropopause occurs at 11 km or 11,000=
m.)
4=
. From
the table of radiosonde data, the pressure of 5=
00 mb occurred over Salem
at 00Z on 16 SEP 2009 at an altitude of [(5240)(5580)(5850)] m. Five
hundred millibars is about one-half of the
atmospheric pressure at sea level. Since air pressure is determined by the
weight of the overlying air, this means one-half of the mass of Salem's atmospher=
e is
above this altitude and one-half below.
5=
. In
the Standard Atmosphere a pressure of 500 mb oc=
curs
at an altitude of 5574 m (18,289 ft.). The altitude of the 500-mb level ove=
r Salem at the time=
of the
sounding was [(higher than)(=
the
same as)(lower than)] that of the Standard
Atmosphere. Therefore, the lower half of Salem's
atmosphere is vertically more "expanded", from the surface to 500=
mb, which is consistent with the existence of warmer =
air.
6=
. Our
Stüve diagram is scaled to allow plotting =
of
atmospheric data up to a pressure of 100 mb (ab=
out 16
km). If the atmospheric pressure at that level is 100 =
mb,
about [(50%)(25%)=
(10%)]
of the atmosphere remains above. We have not reached the top of the atmosph=
ere!
Image
1 is the plotted Stüve diagram for Salem, =
Oregon
(SLE) at 0000Z 16 SEP 2009 (labeled 090916/0000) from the course web=
site
(Upper Air, "Stüves for Select=
ed
Cities"). This Stüve is plotted using=
all
the data from the radiosonde observation. On the
website, under the Upper Air section, "Upper Air Data - Text&qu=
ot;
provides the tabular listing of all data from observations that correspond =
to
the latest plotted soundings. On the graph, the heavy plotted curve to the
right represents temperatures. Winds at various levels are plotted to the r=
ight
of the graph area using the convention of the surface model. For example, t=
he
winds at the surface (lowest arrow point) were from the northeast at
about 5 knots. Additional lines on the Stüve
diagram will be discussed in a later investigation.
7=
. On
the Image 1 Stüve diagram, note the temper=
ature
pattern from 172 mb up to about 160 mb. This layer is an example of [(an isother=
mal
layer)(a temperature inversion=
)(normally
decreasing temperatures)]. This departure from the usual
temperature profile at lower levels is the defining character of the tropopause and the beginning of the stratosphere over=
Salem. Additional
"wiggles" of the temperature profile in the lower stratosphere sh=
ows
the complexity of atmospheric conditions. Knowledge of the finer structure =
of
the temperature profile is often very important in interpreting atmospheric
processes and motions above the surface.
The actual Salem
00Z 16 September 2009 rawinsonde sounding repor=
ted atmospheric
conditions to 8 mb (33,292 m) where the balloon
burst. There was still unsampled air above!
For additional examples, look at the Stüve
diagrams for Anchorage, Alaska
and Hilo, Hawaii
from the Upper Air section. Relative to the Standard Atmosphere, Alaska is typically cooler and Hawaii warmer. Below the table of citi=
es on
the Upper Air Stüves webpage or text data
webpage, a link ("click here") provides access to upper air data =
and rawinsonde plots worldwide.
You or your students might wish to plot the upper air data for your near=
est
site on a blank Stüve diagram ("Blank=
Stüve - T, p lines") found under Extras<=
/i> on
the website. These plots can then be compared with the computer-analyzed
version. View Stüve diagrams when weather
systems pass your location. Atmospheric structure changes during frontal
passages and major storms can be quite dramatic. For additional soundings f=
rom
other upper air sites not provided on the course St&uu=
ml;ve
webpage, use the "click here" link at the bottom of that page.
Record your responses to items in CWS Activities 2A and 2B on the CWS
Answer Form for transmission to your course mentor.
Instructions for Communications with Mentor:
After completing this week's applications, transmit the following work to y=
our
LIT mentor by Monday, 21 September 2009, or as coordinated with your mentor=
:
- Investigations 2A and 2B =
Investigation
Answer Form, from the Study Guide, Week 2, or the DataStreme
Atmosphere website.
- Investigation 2B page 2B-3
from the Weather Studies Investigations Manual.
- Current Weather Studies
activities 2A and 2B CWS
Answer Form.
Note: Permission is hereby granted to DataSt=
reme
Atmosphere Project participants for the reproduction, without alteration, of
materials contained in DataStreme Atmosphere
publications and delivered via the DataStreme
Atmosphere website for non-commercial use in schools or in other teacher en=
hancement
activities on the condition their source is acknowledged. This permission d=
oes
not extend to delivery by electronic means.
Return to <=
span
class=3DSpellE>DataStreme Atmosphere website
©Copyright, 2009, American Meteorological Society