IN THE NAME OF GOD SYNOPTIC METEOROLOGY CHAPTER ONE: METEOROLOGICAL STATIONS AND DATA SUMMER, 2011.

IN THE NAME OF GOD

SYNOPTIC METEOROLOGY

CHAPTER ONE:

METEOROLOGICAL STATIONS AND DATA

SUMMER, 2011

Meteorological stations are used for observing meteorological parameters in the earth’s surface and upper of the atmosphere.

The main surface-based stations are:(a)Surface synoptic stations: (i) Land stations: - Manned surface stations; - Automatic surface stations;

Synoptic Meteorology (Chapter 1): METEOROLOGICAL STATIONS

• (i) Sea stations:• - Fixed sea stations:• - Ocean weather stations;• - Lightship stations;• - Fixed platform stations;• - Island and coastal stations;

• - Mobile sea stations:• - ship stations;

• - Automatic sea stations:• - Fixed stations• - Mobile stations• - Buoy stations


• (i) Upper-air synoptic stations:• - Rawinsonde station;• - Radiosonde station;• - Radiowind station;• (C) Aircraft Meteorological stations;• (d) Climatological stations;• (e) Agricultural meteorological stations; and• (f) Special stations which include Weather radar

stations, Radiation stations, Wind profilers and …


• Surface synoptic station may be manned or partly or fully automated and include land stations and fixed and mobile stations.

• Each synoptic station should be located so as to give meteorological data representative of the area in which it is situated.

• The main standard times foe surface synoptic observations are 0000, 0600, 1200 and 1800 UTC.

• The intermediate standard times for surface synoptic observations are 0300, 0900, 1500 and 2100 UTC.

Synoptic Meteorology (Chapter 1): SURFACE SYNOPTIC STATIONS

• The interval, in general, of surface synoptic stations should not exceed 250 km (or 300 km in sparsely populated areas).

• Surface synoptic observations recorded at a manned synoptic land station consist of observations of the following meteorological parameters: Present weather, Past weather, wind direction and speed, cloud amount, type of cloud, height of cloud base, visibility, air temperature, humidity, atmospheric pressure, Pressure tendency, Characteristic pressure tendency, Extreme temperature, Amount of precipitation, …

Synoptic Meteorology (Chapter 1): SURFACE SYNOPTIC STATIONS

• The standard times of upper-air synoptic observations should be 0000, 0600, 1200, 1800 UTC.

• An upper-air synoptic observations of one or more of the following meteorological elements: Atmospheric pressure, Air temperature, Humidity and Wind direction and Speed.

• Upper-air observations should be made and reported at least at 0000 UTC and 1200 UTC.

Synoptic Meteorology (Chapter 1): UPPER-AIR SYNOPTIC STATIONS

• The network of climatological stations give a satisfactory representation of all types of terrain in the territory of the concerned.

• At a principal climatological station, observations should be made of all or most of the following meteorological elements where appropriate: Weather, Wind direction and speed, Cloud amount, Type of cloud, Height of cloud base, Visibility, Air temperature (including extreme temperature), Humidity, Atmospheric pressure, Precipitation amount, Snow cover, Sunshine duration and/or solar radiation, Soil temperature (at 5, 10, 20, 50, 100, 150 and 300 cm).

Synoptic Meteorology (Chapter 1): CLIMATOLOGICAL STATIONS

MiMiMjMj YYGGiw IIiii iRiXhVV

Nddff 1snTTT 2snTdTdTd 3P0P0P0P0

4PPPP 5appp 6RRRtR 7wwW1W2

8NhCLCMCH 222// (0SnTWTWTW) 1PWaPWaHWaHWa

2PWPWHWHw 3dw1dw1dw2dw2 4PW1PW1HW1HW1 5PW2PW2HW2HW2

333 1snTxTxTx 2snTnTnTn 3Ejjj

4E'sss 5j1j2j3j4 7R24 R24 R24 R24 8NsChshs

Synoptic Meteorology (Chapter 1): LAND STATION SURFACE SYNOPTIC CODE FM 12-IX SYNOP

•MiMiMjMj - Bulletin Header

MiMi : For land station, this will be AA. It identifies the bulletin as being composed of “SYNOP” message from land station. MjMj : For land station, this will be XX.

•YYGGiw - Observation Date-Time Group

YY : Day of the month of the observation. GG : Actual Time of the observation in UTC. iw : Wind speed indicator (code table 1855).


Code Table 1855 iw — Indicator for source and units of wind speed


Code Figure Description

0 Wind speed estimated, reported in meters per second.

1 Wind speed obtained from anemometer, reported in meters per second.

3 Wind speed estimated, reported in knots.

4 Wind speed obtained from anemometer, reported in knots.

/ Wind speed not available.

• IIiii - International Index Number II : Block number. iii : Station number.

• iRiXhVV - Precipitation Inclusion-Exclusion / Type operation / Cloud height /Visibility Group

iR : Indicator for inclusion or omission of precipitation data. Encoded using code table 1819.

Code Table 1819 iR


Code Precipitation data are recorded Group 6RRRtR is:

0 In Sections 1 and 3 Included in both sections

1 In Sections 1 Included

2 In Sections 3 Included

3 In neither section 1 or 3 Omitted (precipitation amount = 0)

4 In neither section 1 or 3 Omitted (precipitation amount not available)

• iX : Type of station operation indicator (manned or automatic) and whether group 7 is encoded in section 1.

code table 1860


Code Type of station Group 7wwW1W1

1 Manned Included

2 Manned Omitted (no significant phenomenon to report)

3 Manned Omitted( no observation, data not available)

4 Automatic Included using code tables 4677 and 4561

5 Automatic Omitted (no significant phenomenon to report)

6 Automatic Omitted (no observation, data not available)

7 Automatic Included using code tables 4680 and 4531

• h : Height above the surface of the base of the lowest cloud seen.Code table 1600 h


Code figure

Feet Meters

0 0-100 0-50

1 100-300 50-100

2 300-600 100-200

3 600-900 200-300

4 900-1900 300- 600

5 1900-3200 600-1000

6 3200-4900 1000-1500

7 4900-6500 1500-2000

8 6500-8000 2000-2500

9 8,000 or higher or no cloud 2500 or higher or no cloud

/ Height of base of cloud is not known.

• VV : Horizontal surface visibility• The code is direct reading in units of 100 m from 0 to 50.

• The code figures 51 to 55 are not used.

• For code figures 56 to 80, 50 is subtracted and the remaining figure is direct reading in units of km.

• Code figures 90 to 99 are used to report visibility in the ship synoptic code.


• Nddff - Total cloud cover and wind group

N : Total cloud cover.


Code figure Cloud amount (oktas) Cloud amount (tenths)

0 0 0

1 1/8 or less, not zero 1/10 or less, not zero

2 2/8 2/10 - 3/10

3 3/8 4/10

4 4/8 5/10

5 5/8 6/10

6 6/8 7/10 – 8/10

7 7/8 or more but not 8/8 9/10 or more, but not 10/10

8 8/8 10/10

9 Sky obscured, or cannot be estimated.

/ No measurement made

• dd : True wind direction in tens of degrees, from which the wind is blowing. (Use code table 0877). For example 01 is used for 5° to 14° and 10 is used for 95° to 104°

• ff : Wind speed in units indicated by iw.

Code Table 1855 iw


Code figure Description

0 Wind speed estimated, reported in meters per second.1 Wind speed obtained from anemometer, reported in meters per

second.3 Wind speed estimated, reported in knots.4 Wind speed obtained from anemometer, reported in knots./ Wind speed not available.

• 1snTTT - Air Temperature Group

• 1 : Identifier for the air temperature group.• sn : Sign of the temperature. 0 = temperature is positive or zero, 1 = temperature is negative.• TTT : Air temperature in tenths of degrees Celsius.


• 2snTdTdTd - Dew Point Temperature Group or Relative Humidity.

• 2 : Identifier for the dew point temperature group.• sn : Sign of the dew point temperature. 0 = dew point temperature is positive or zero, 1 = dew point temperature is negative, 9 = relative humidity follows.• TdTdTd : Dew point temperature in tenths of

degrees Celsius.


• 3P0P0P0P0 - Station Pressure Group

• 3 : Identifier for the station pressure group.• P0P0P0P0 : Pressure at station level, in tenths of a

hPa. If the station pressure is more than 999.9 hPa, drop

the thousands digit of the pressure.

Example: station pressure = 1016.7 hPaP0P0P0P0= 0167


• 4PPPP : Sea Level Pressure Group

• 4 : Identifier for sea level pressure group.• PPPP : Sea level pressure. This is the station

pressure “reduced” to mean sea level in tenths of a hPa.

If the sea level pressure is more than 999.9 hPa, the thousands digit of the pressure is omitted.


• 5appp - 3-Hour Pressure Tendency Group

5 : Identifier for the group reporting pressure tendency and pressure change for the three hours preceding the time of observation.

a : Characteristic of the pressure tendency during the three hours preceding the time of the observation. Use code table 0200.

ppp : Actual change in the pressure during the three hours ending at the actual time of the observation, expressed in tenths of hPa.


Code Table 0200 Characteristic of Pressure Tendency (a)


0 Increasing, then decreasing; atmospheric pressure the same or higher than 3 hours ago.

1 Increasing, then steady; or increasing, then increasing more slowly.

Atmospheric pressure now higher than 3 hours ago.2 Increasing (steadily or unsteadily).

3 Decreasing or steady, then increasing; or increasing, then increasing more rapidly.

4 Steady; atmospheric pressure the same as 3 hours ago.

5 Decreasing, then increasing; atmospheric pressure the same or lower than 3 hours ago.

6 Decreasing, then steady; or decreasing, then decreasing more slowly.

Atmospheric pressure now lower than 3 hours ago.7 Decreasing (steadily or unsteadily)

8 Steady or increasing, then decreasing; or decreasing, then decreasing more rapidly.

• 6RRRtR - Identifier for the precipitation group• RRR : Total amount of precipitation fallen during the period

preceding the time of observation, as indicated by tR.

Code table 3590 Amount of precipitation


Code figure Amount (mm) Code figure Amount (mm)000 Not used 990 Trace001 1 991 0.1002 2 992 0.2003 3 993 0.3004 4 994 0.4Etc. Etc. 995 0.5987 987 996 0.6988 988 997 0.7989 989 998 0.8

999 0.9

• tR : Length of time covered by the group.Code table 4019


Code figure Duration of period of precipitation

1 6 hours preceding time of observation2 12 hours preceding time of observation3 18 hours preceding time of observation4 24 hours preceding time of observation5 1 hour preceding time of observation.6 2 hour preceding time of observation.7 3 hour preceding time of observation.8 9 hour preceding time of observation.9 15 hour preceding time of observation.

• 7wwW1W2 - Present and Past Weather Group reported from an manned weather station.

7 : Identifier for the present and past weather groupww : Present weather at the time of the observation.W1W2 : Past weather. The most significant and the second most significant

past weather during the period.


Code Code table 4561 Past weather

0 Cloud covering 1/2 or less of the sky throughout the appropriate period.

1 Cloud covering more than 1/2 of the sky during part of the appropriate period andcovering 1/2 or less during part of the period.

2 Cloud covering more than 1/2 of the sky throughout the appropriate period.

3 Sandstorm, dust storm, or blowing snow.

4 Fog or ice fog or thick haze. 7 Snow, or rain and snow mixed.

5 Drizzle. 8 Shower(s).

6 Rain. 9 Thunderstorm(s) with or without precipitation.

Synoptic Meteorology (Chapter 1): LAND STATION SURFACE SYNOPTIC CODE FM 12-IX SYNOP Table 4677. ww

• 8NhCLCMCH - Cloud Type Group

• 8 : Identifier of the type of cloud group.• Nh : Amount of low cloud present. Use code table 2700 with the Nddff

group.

• CL : Clouds of the genera stratocumulus, stratus, cumulus, and cumulonimbus. Use code table 0513.

• CM : Clouds of the genera Altocumulus, Altostratus, and Nimbostratus. Use code table 0515.

• CH : Clouds of the genera Cirrus, Cirrocumulus, and Cirrostratus. Use code table 0509.


Code table 0513 CL


Code Discription

0 No CL clouds1 Cumulus humilis or cumulus fractus other than of bad weather,* or both.

2 Cumulus mediocris or congestus, with or without cumulus of species fractus or humilis or stratocumulus, all having their bases at the same level.

3 Cumulonimbus calvus, with or without cumulus, stratocumulus or stratus.4 Stratocumulus cumulogenitus.5 Stratocumulus other than stratocumulus cumulogenitus.6 Stratus nebulosus or stratus fractus other than of bad weather, or both.

7 Stratus fractus or cumulus fractus of bad weather.

8 Cumulus and stratocumulus other than stratocumulus cumulogenitus, with bases at different levels.

9 Cumulonimbus capillatus (often with an anvil), with or without cumulonimbus calvus, cumulus, stratocumulus, stratus or pannus.

/ CL clouds invisible owing to darkness, fog, blowing dust or sand, or … .


Code table 0515 CM

Code Discription

0 No CM clouds

1 Altostratus translucidus

2 Altostratus opacus or nimbostratus

3 Altocumulus translucidus at a single level.

4 Patches (often lenticular) of altocumulus translucidus, continually changing and occurring at one or more levels.

5 Altocumulus translucidus in bands.

6 Altocumulus cumulogenitus (or cumulonimbogenitus)

7 Altocumulus translucidus or opacus in two or more layers.

8 Altocumulus castellanus or floccus.

9 Altocumulus of a chaotic sky, generally at several levels.

/ CM clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena, or because of continuous layer of lower clouds.


Code Discription

0 No CH clouds

1 Cirrus fibratus, sometimes uncinus, not progressively invading the sky.

2 Cirrus spissatus, in patches or entangled sheaves.

3 Cirrus spissatus cumulonimbogenitus.

4 Cirrus uncinus or fibratus, or both, progressively invading the sky.

5 Cirrus (often in bands) and cirrostratus, or cirrostratus alone, progressively invading the sky.

6 Cirrus (often in bands) and cirrostratus, or cirrostratus alone, progressively invading the sky; they generally thicken as a whole;.

7 Cirrostratus covering the whole sky.

8 Cirrostratus not progressively invading the sky and not entirely covering it.

9 Cirrocumulus alone, or cirrocumulus predominant among the CH clouds.

/ CH clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena, or because of a continuous layer of lower clouds.

Code table 0509 CH

• 222// - Section 2 Identifier Group for Reporting Wind and Swell Waves

• (0SnTWTWTW) - Sea-surface temperature group.

• 0 : Identifier for sea-surface temperature group.

• sn : Sign of the temperature:

0 = temperature is positive or zero;

1 = temperature is negative.

• TWTWTW : Sea-surface water temperature given in units of tenths of degree Celsius.


• 1PWaPWaHWaHWa - Instrumental wave data group.

• 1 : Identifier for the instrumental wave data group.

• PWaPWa : Period of the waves obtained by instrumental methods, in whole seconds.

• HWaHWa : Height of waves, obtained by instrumental methods, in units of 0.5 meters. See wave height table below.

• 2PWPWHWHW - Wind Wave Group.This group is used to report wind waves when instrumental wave data is not available. The period and

wave heights are estimated.

• 2 : Identifier for the non-instrumental wind wave group.• PWPW : Estimated period of the wind wave in whole seconds.• HWHW : Estimated height of the wind waves in units of half-

meters.


• 3dw1dw1dw2dw2 - Swell Wave Direction Group

3 : Identifier for the swell wave direction group.

dw1dw1 : The true direction, in tens of degrees from which the first swell wave system is moving. Code table 0877 is used.

dw2dw2 : The true direction, in tens of degrees from which the second swell wave system is moving. Code table 0877 is used.


• 4PW1PW1HW1HW1 - First Swell System Group4 : Identifier for the first swell system group.

PW1PW1 : Period of the first swell system in whole seconds.

HW1HW1 : Average height of the significant swell waves of the first swell system reported in half-meters.

• 5PW2PW2HW2HW2 - Second Swell Wave System Group5 : Identifier for the second swell wave system group.PW2PW2 : Period of the second swell wave system in whole seconds.HW2HW2 : Average height of the significant swell waves of the second

swell system.


• 333 - Group Identifier for Section 3• 1snTxTxTx - Maximum Temperature Group.1 : Identifier for the maximum temperature group.

sn : Sign of the temperature.

0 = positive or zero maximum temperature.

1 = negative maximum temperature.

TxTxTx : Maximum temperature in tenths of degrees Celsius.

• 2snTnTnTn - Minimum Temperature Groupsn : Sign of the temperature. 0 = positive or zero; 1 = temperature is negative.TnTnTn : Minimum temperature in tenths of degrees Celsius.


• 7R24 R24 R24 R24 - 24-Hour Precipitation Group

7 : Identifier for the 24-hour precipitation group.

R24 R24 R24 R24 : Precipitation amount for the past 24 hours. The total amount of liquid precipitation and the water equivalent for solid precipitation is encoded to the nearest tenths of millimeters. It is coded 79998 for 999.8 mm or more, and if only a trace has fallen, encode 79999.


• 8NsChshs - Individual Cloud Layer Group

8 : Identifier for the individual cloud layer group. The group may be repeated up to three times (four if one layer is cumulonimbus) in one report.

Ns : The amount of the individual cloud layer reported. Use code table 2700. See the table with the Nddff group.

C : Cloud type for the layer. Use code table 0500.

hshs : Height above the ground of the base of the cloud layer. Use code table 1677.


IN THE NAME OF GOD SYNOPTIC METEOROLOGY CHAPTER ONE: METEOROLOGICAL STATIONS AND DATA SUMMER, 2011.

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