1- Geographical Situation
and Relief
Northern Hemisphere
Latitude: Between 7°11' North and 9°39'
North
Longitude: Between 77° 10' West and 83°
03' West
Panama is located in the inter-tropical zone
close to the terrestrial equator.
It is a thin strip of land orientated from
East to West and its coasts are washed by the Caribbean Sea
and the Pacific Ocean.
One of the basic elements that define the weather
is the orography since the relief not only affects the thermic
regime causing a lowering of the temperature in the air with
the elevation, but it also affects the atmospheric circulation
of the region and modifies the pluviometric airflow in general.
2- Oceanography
The big oceanic bodies from the Atlantic and
the Pacific are the main sources for a high percentage of
humidity in our environment and, due to the thin strip of
land that separates these oceans, the weather shows a strong
influence from the sea. The ocean-atmosphere interaction determines,
in great measure, the properties of heat and humidity of the
air masses circulating over the oceans. The marine air currents
are closely related to the rotation of the earth and the winds.
3- Meteorology
The semi-permanent anti-cyclone from the North
Atlantic, noticeably affects the weather conditions in our
country because the Northeast Trade Winds are originated in
this system. These Trade Winds reach our country through the
lower layers of the atmosphere and have a strong influence
on the weather of the Republic.
There is a zone of confluence of the Trade
Winds from both hemispheres (North and South) that affects
the weather of those places located under its influence and
is particularly important to our country: the Inter-tropical
Convergence Zone (ITCZ), which moves following the apparent
movement of the sun during the year. This north-south ITCZ
migration produces the two seasons (dry and rainy) typical
of most of our territory.
Weather Classification according to W.
Köppen
The index that provide the limits between the
different types of weather according to Köppen's system
for weather classification, agrees with the groups of vegetation
and are based on the average monthly and annual temperature,
and the average monthly and annual rainfall.
This type of classification system distinguishes
climatic zones, and within them, the different types of weather
thus resulting in 13 basic types of climates:
Two climatic zones have basically been identified
for Panama:
Zone A: Includes the tropical
rainy climates where the average monthly temperature all year
long is over 18ºC. Within this climatic zone, tropical
plants grow requiring a lot of heat and humidity, in other
words, in megathermic vegetation zones.
Zone C: Includes the rainy
temperate climates where the warmest average monthly temperature
is higher than 10º C and the coldest average monthly
temperature is 18º C, but higher than -3º C. The
typical vegetation within this climatic zone needs moderate
heat and enough humidity, but generally is not resistant to
pluviometric or thermic extremes; the zones identified have
massothermic vegetation.
Pluviometric
Systems by region
Pacific Region: It is characterized
by abundant rainfall, with a moderate to strong intensity,
together with electrical storms specially during the afternoon.
The rainy season definitely starts during May and lasts until
November, being September and October the most rainy months
of the year. During this season, a dry period often occurs
between the months of July and August, and it is commonly
known as the "Veranillo" (Indian Summer).
The
period between December and April is considered to be the
dry season. The highest levels of precipitation in this region
are generally related to well organized atmospheric systems,
like the waves and the tropical cyclones (depressions, tropical
storms and hurricanes), and the ITCZ.
Central
Region: Within this region, rainfall generally occurs
after midday and it is caused by the predominant flows coming
from the Caribbean or from the Pacific Ocean. These are in
between moderate and strong rainfalls, together with electrical
activity and strong winds. This region is considered the most
continental of the country's geography, therefore, the thermic
and orographic contrasts play their roles.
Atlantic
Region: It rains almost all year long in this region.
There is abundant rainfall between December and February mostly
caused by the incursions of the frontal systems from the northern
hemisphere towards the tropical latitudes. The rest of the
year, rainfall is associated to the tropical atmospheric systems
that move from the Caribbean Basin, the sea breezes, and the
diurnal warming of the terrestrial surface.
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