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wind_rose.pptx
1. Wind Rose
Prepared by : Abdul Rahim Hour
Hesham A. Abu Ghaly
Supervisor :
Prof.dr. eng shafik Jendia
2. INTRODUCTION
A wind rose depicts the frequency of incidence of winds in each of the
particular wind direction sectors and wind speed modules for a
specified site and time period. The most regular structure consist of a
circle from which eight or sixteen lines come out, one for each
direction. The length of each line is comparative to the occurrence of
wind from which direction and the occurrence of calm conditions is
entered in the center.
3. INTRODUCTION
The wind roses are widely applicable in the fields such as
Environmental impact assessment, industrial emissions
measurements, oceanography, wind energy, agriculture
engineering, ambient air monitoring, air quality measurements,
indoor air quality testing, air dispersion modelling, noise
impact modelling and soil impact modelling.
4. Wind Rose
The wind rose is the time
honored method of
graphically presenting the
wind conditions, direction and
speed, over a period of time at
a specific location.
5. Wind Rose
Rose wind is a naval term given to
those original four known geographically
(North, South, East and West).
These trends are called according to the
names of the stars in the sky, a traditional
method of ancient sailors to guide their
navigational ways.
6. Historical view
In the sixteenth century,(Ibn Majid Albahhar) invented the rose wind and
used it with a magnetic compass, and Fractionated Rose wind on the
horizon circle by the original to 32 sections.
Ibn Majid has made North refers to the (Aljah).
South refers to the (Kotb Suhail) or the (star Suhail).
the Middle refers to (Matla Najem Altaer).
and west to the (Matla Najem Altaer).
7. How to read Wind Rose
By Using a polar coordinate system of gridding, the
frequency of winds over a long time period is
plotted by wind direction, with color bands
showing wind ranges.
The directions of the rose with the longest spoke
show the wind direction with the greatest frequency
1 Knot = 1.852 Km/h
8. Steps to develop a wind rose diagram from
hourly observations are:
1. Analysis for wind direction
2. Determination of frequency of wind in a
given wind direction
3. Analysis for mean wind speed
4. Preparation of polar diagram
9. Steps to develop a wind rose diagram from
hourly observations are:
* % Frequency = Number of observations *
100/Total Number of Observations
* Direction: N, NNE, ------------------------,NNW,
Calm (depend on the kind of wind rose )
* Wind speed: Calm, 1-3, 4-6, 7-10, (depend
on categories )
10. How to read Wind Rose
The wind rose located in the top right
corner of each data map shows the general
wind direction and speed for each sampling
period. The circular format of the wind rose
shows the direction the winds blew from
and the length of each "spoke" around the
circle shows how often the wind blew from
that direction. For example, the wind rose
above shows that during this particular
sampling period the wind blew from the
west 30% of the time, and from the north
and the northeast 12% of the time, etc.
11. How to read Wind Rose
The different colors of each spoke
provide details on the speed, in knots
(1 knot=1.15 mph), of the wind from
each direction. Using the example
above, the longest spoke shows the
wind blew from the west at speeds
between 1-4 knots (light blue) about
4% of the time, 4-7 knots (dark
green) about 18% of the time and 7-
11 knots (dark blue) about 7% of the
time.
12. Airport Runway Orientations
• The analysis of wind data is fundamental in
many sectors, One of such sectors is the designing
of airport runways.
13. Airport Runway Orientations
The orientation of runway depends upon the direction
of the wind and some extent on the area available for
development.
14. Airport Runway Orientations
Wind perpendicular to the runway (crosswinds) may
cause serious accidents, especially during landing and
for small airplanes. Then analysis of past accidents
(van Es, van der Geest & Nieuwpoort, 2001) has
demonstrated that the probability of occurrence of an
accident increases with increasing crosswind
conditions.
15. Airport Runway Orientations
The direction of the runway Controls the layout of
the other airport facilities, such as passenger
terminal, taxiways, apron configurations,
circulation roads and parking facilities.
16. Runway Design:
According to FAA Standards “150- 530013A”,
runways should be oriented so that aircraft can
take off and/or land at least 95% of the time with
out exceeding the allowable crosswinds.
Runway are always oriented in the direction of
prevailing wind
