Name _________________________

Date __________________________

Meteorology 430

Fall 2010

Lab 2

**Review of Basic
Techniques**

**(Due Beginning of
Class, Friday 10 September)**

1. All labs are to be kept in a three hole
binder. Turn in the binder when

you have finished the
Lab.

2. **Show
all PROCEDURE**. No credit given
if only

answer is provided.

3. Unless otherwise noted, you may work
together. But remember, YOU

are the one who will
be responsible for understanding the material for

exams and when you
are out in the profession. So
STRIVE to

understand what you
are doing. Don't let someone else
do your

thinking for you.

1. Determine the value of a degree in km
at 40^{o}N latitude (trigonometry).

a = radius of earth =
6370 km

r
= radial distance to the axis of rotation which,

by
simple geometry, = a cos phi where phi is the latitude

Circumference = 2π R

Distance
(km) of 1^{o } = (Circumference)/360^{ o}

For
latitude R = a and a degree is (2π 6370 km )/360^{ o} = 111.3 km

For longitude R = r and a degree is (2π 6370 km cos 40) = 85.3 km

2. (a) Give
the PHYSICAL INTERPRETATION of each term of

equation (cartesian coordinate) below, where V is the three dimensional
wind vector:

A B C

(b) __Name__
each term in equation.

(c) Solve
the equation for the local tendency.

(d) Expand
term "C".

(e)
Assume
that **dT/dt = 0** for the chart given
and that there **is no vertical motion**.
Determine the local temperature tendency at the station reporting the wind of
225^{o}, 25 knots, shown in the diagram below. External grid points indicated by
crosses are 100 km distant from station, nominally placed at center of implied
x-y coordinate cross. Isotherms
are north-south.

(a) A is the temperature change experienced by the
moving parcel, as if a thermometer moved with the air parcel.. B is the temperature change measured at
a location fixed with respect to the surface of the earth. C is the contribution to the local
temperature change made by cold or warm advection.

(b)

Term A

Term B

Term C

(c)

(d)

(e)

u and v are the horizontal
wind components, but there is no north/south

temperature gradient in this
case. Hence,

where u = 25 knots (sin 45) =
17.68 knots = 32.5 km h^{-1}

The temperature change will
be entirely due to advection,

-1.6^{o} C h^{-1
}

3. (a) Physically interpret the terms to the right of the equals
sign in

equation (2) (basic calculus)

(b) Equations (3a,b) are the geostrophic
wind components. Put (3a,b) into (2) to determine the divegence of
the geostrophic wind. Assume g
and f are constants. I realize we
have not discussed divergence, or horizontal divergence. But this question involves you working
with the mathematical operations, not the
meteorological interpretation.

4. (a) Physically interpret the terms to the
right of the equals sign in

equation (2) (basic calculus)

(2)

(3a,
b)

(b) Equations
(3a,b) are the geostrophic wind components. Put (3a,b) into
(2) to determine the divegence of the geostrophic wind. Assume g
and f are constants.

(a) ∂u/∂x is the horizontal shear of the west wind along the x axis **or**

the
variation of the west wind along the x axis **or **the variation of the west wind speed along the x axis.

∂v/∂y
is the horizontal shear of the south wind along the y axis **or**

the
variation of the south wind along the y axis **or **the variation of the south wind speed along the y axis.

(b)

(1)

(2a,
b)

Put
Eq 2(a,b) into (1)

(3a)

(3b)

Equation (3b) states that the horizontal divergence of the geostrophic wind is related to the variation of north-south slope of an isobaric surface along the x-axis and to the variation of the west-east slope of an isobaric surface along the y-axis. However, the second derivatives are identical but opposite sign, so the horizontal divergence of the geostrophic wind

**DIV _{h} = 0 **(4)

4. Obtain a plot of the
NAM initialization of 500 mb heights and absolute
vorticity AND surface pressure with 1000-500 mb thickness at
initialization time for 12 UTC 31 August 2010.

(a)
Write out the
script you executed on the command line to obtain
this.

(b)
Append -p on the
command line after the command to print a
black and white copy to turn in with this lab.

5. (a) Use
the script mod_grib -p to print out a copy of the 500 mb heights for 12 UTC 31 August
2010.

(b) Annotate
troughs and ridges as we did in Metr 201 (and Metr 400).

6. For
the sounding distributed (KOAX 12 UTC 31 August 2010), determine the

(a)
LCL, LFC and CAPE
and CIN areas for 12 UTC (first copy);

(b)
CT, and CCL (second
copy)

Make sure you draw everything neatly
and use the correct color conventions.