Introduction The searching results explanations of meteorological data Depending on the parameter, the instrumental measuring or visual observation method is used for the meteorological observations. Instrumentally measured results are recorded in a digital format with respective units, but the visual results of the observations are recorded in coded form. Separated meteorological parameters is measured instrumental and in data searching results information is described in coded form or casts further light on the results And they are: wind direction; precipitation amount. Information from data searching results is described with codes these visually observed meteorological parameters: state of ground surface; snow cover vicinity extent; amount of cloud and its type; weather. All meteorological observations/measurements results are offered by Latvian time (winter or summer), except sunshine duration and solar radiation data that are offered by a true solar time (depending on the geographical location of each station and the position of the sun in the sky. Wind direction Wind direction measures in degrees Occasion described with codes, when is calm or variable wind. Precipitation amount Code 0 Calm 999 Variable Precipitation amount is offered by 3 parameters: precipitation amount between terms; precipitation amount, ly sum; precipitation amount by pluviograph Explanation Parameter Precipitation amount between terms is measured manually at fixed observation term and characterized precipitation amount sum observation term interval. Parameter Precipitation amount, ly sum is measured automatically and characterized precipitation amount sum every. Parameter Precipitation amount by pluviograph is registered continuous mode in time period from May 1st to October 31st (when air minimal temperature is stable above 0 C) and characterized precipitation amount sum from rain beginning to the end of every 10 minutes interval Occasions are not registered, when rain precipitation amount is not over 2.5 mm. Below is given explanation for special records meaning in results field. Parameter explanation Record in Precipitation amount Precipitation amount, results field between terms ly sum 0 Precipitation trace 1 Both precipitation trace, and no precipitation Precipitation amount by pluviograph Empty field No precipitation lack data No precipitation or rain precipitation amount was not over 25 mm -9999 measurement is rejected 2 1 Precipitation trace precipitation amount less than 0.05 mm; 2 In the case of rejected data at the end of rain indicates the precipitation sum of one rain, which is measured manually between observations terms. LEGMC The searching results explanations of meteorological data 1
State of ground surface State of ground surface is described coded form. Snow cover vicinity extent Description of state of ground Code surface 0 Dry 1 Moist 2 Wet, pools 3 Flooded 4 Frozen 5 Snow 10% in vicinity 6 Very dry Snow cover vicinity extent is estimated visually according to 10 ball scale For coding are used numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 which shows, that ground surface is covered with snow respectively 10, 20, 30, 40, 50, 60, 70, 80, 90 un 100% of visible vicinity of station. Amount of cloud Amount of cloud is estimated in balls amount of total cloud and amount of low cloud. Cloud type Amount of cloud, ball Sky coverage Weather condition description 0 No clouds, sky clear, sunny 1 No significant clouds, separately clouds 2 3 Few clouds, the sun is shining 4 Variable amount of cloud; sunny day, however, occasionally the sky is covered with clouds; the sky is 5 partly cloudy 6 7 8 Mostly cloud, sometimes sun is shining; broken clouds 9, 12 Cloudy, translucent clouds 10 13 Overcast, the sky is covered with thick/dark/rainy clouds, the sky is covered with thick clouds Clouds cannot be seen because of fog, snowstorm and other phenomena Cloud type are described in coded form for low, middle and high clouds. Low clouds type Middle clouds type High clouds type Code Name Code Name Code Name 0 No clouds 0 No clouds 0 No clouds 1-2 Cumulus 1 Altostratus 1-4 Cirrus 3, 9 Cumulonimbus 2 Altostratus/Nimbostratus 5-8 Cirrostratus 4-5 Stratocumulus 3-6,8,9 Altocumulus 9 Cirrocumulus 6-7 Stratus 7 Altostratus/Altocumulus 8 Startocumulus/ Cumulus LEGMC The searching results explanations of meteorological data 2
Weather conditions Weather conditions characterizes atmospheric phenomena and cloudy changes, information is written in code form. Weather conditions are offered in the form of 3 parameters: Present weather; Past weather 1; Past weather 2. Parameter Present weather characterizes weather conditions 10 minutes before observation term and what weather conditions has been one before term or during the preceding. Parameters Past weather 1 and Past weather 2 characterizes weather conditions between observation terms. Code 00 Cloud development not observed or not observable 01 Clouds generally dissolving or becoming less developed 02 State of sky on the whole unchanged 03 Clouds generally forming or developing Characteristic change of the state of sky during the past 04 Visibility reduced by smoke (forest fires, industrial smoke) at the observation term or/and during the preceding (at the station or visible distance) 05 Haze at the observation term or/and during the preceding (at the station or visible distance) 06 Widespread dust in suspension in the air, not raised by wind at or near the station at the time of observation 07 Dust or sand raised by wind at or near the station at the time of observation, but no well-developed dust whirl(s) or sand whirl(s), and no duststorm or sandstorm seen; or, in the case of ships, blowing spray at the station 08 Well-developed dust whirl(s) or sand whirl(s) seen at or near the station during the preceding or at the time of observation, but no duststorm or sandstorm 09 Duststorm or sandstorm within sight at the time of observation, or at the station during the preceding 10 Mist (visibility 1 km) at the observation term (at the station or visible distance) 11 Shallow fog/ice fog - patches (not deeper than 2 m on land) at the observation term (at the station or visible distance) 12 Shallow fog - dense layer (not deeper than 2 m on land) at the observation term (at the station visible distance) 13 Lightning visible at the observation term (at the station or visible distance), no thunder heard 14 Precipitation within sight, not reaching the ground or the surface of the sea at the observation term visible distance, but not at the station 15 Precipitation within sight, reaching the ground or the surface of sea at the observation term visible distance, but not at the station (distant 5 km from station) 16 Precipitation within sight, reaching the ground or the surface of sea at the observation term near to, but not at the station 17 Thunderstorm (near or distant) at the observation term, but no precipitation at the time of observation 18 Squalls at the observation term or/and during the preceding 19 Water spout at the observation term or/and during the preceding 30 Slight, moderate dust-, sandstorm without precipitation at the observation term has decreased during the preceding 31 Slight, moderate dust-, sandstorm without precipitation at the observation term no appreciable change during the preceding 32 Slight, moderate dust-, sandstorm without precipitation at the observation term has begun or has increased during the preceding LEGMC The searching results explanations of meteorological data 3
Code 33 Heavy dust-, sandstorm without precipitation at the observation term has decreased during the preceding 34 Heavy dust-, sandstorm without precipitation at the observation term no appreciable change during the preceding 35 Heavy dust-, sandstorm without precipitation at the observation term has begun or has increased during the preceding 36 Slight or moderate drifting snow at the observation term (generally low/below eye level) 37 Heavy drifting snow at the observation term (generally low/below eye level) 38 Slight or moderate drifting blowing or blowing snow with or without precipitation at the observation term (generally high/above eye level) 39 Heavy drifting blowing or blowing snow with or without precipitation at the observation term (generally high/above eye level) 40 Fog or icy fog at the observation term visible distance from station 41 Fog or icy fog in patches at the observation term at a visible distance from station 42 Fog or icy fog at station at the observation term, sky visible and has become thinner during the preceding 43 Fog or icy fog at station at the observation term, sky invisible and has become thinner during the preceding 44 Fog or icy fog at station at the observation term, sky was visible and no appreciable change during the preceding 45 Fog or icy fog at station at the observation term, sky invisible and no appreciable change during the preceding 46 Fog or icy fog at station at the observation term, sky visible and has begun or has thicker during the preceding 47 Fog or icy fog at station at the observation term, sky invisible and has begun or has thicker during the preceding 48 Fog, depositing rime at station at the observation term and sky visible 49 Fog, depositing rime at station at the observation term and sky invisible 50 Slight, not freezing drizzle at the observation term, intermittent during preceding 51 Slight, not freezing drizzle at the observation term, continuous during preceding 52 Moderate, not freezing drizzle at the observation term, intermittent during preceding 53 Moderate, not freezing drizzle at the observation term, continuous during preceding 54 Heavy, not freezing drizzle at the observation term, intermittent during preceding 55 Heavy, not freezing drizzle at the observation term, continuous during preceding 56 Slight, freezing drizzle and glaze formed at the observation term 57 Moderate or heavy, freezing drizzle and glaze formed at the observation term 58 Slight drizzle with rain at the observation term 59 Moderate or heavy drizzle with rain at the observation term 60 Slight, not freezing rain at the observation term, intermittent during preceding 61 Slight, not freezing rain at the observation term, continuous during preceding 62 Moderate, not freezing rain at the observation term, intermittent during preceding 63 Moderate, not freezing rain at the observation term, continuous during preceding 64 Heavy, not freezing rain at the observation term, intermittent during preceding 65 Heavy, not freezing rain at the observation term, continuous during preceding 66 Slight, freezing rain and glaze formed at the observation term LEGMC The searching results explanations of meteorological data 4
Code 67 Moderate or heavy, freezing rain and glaze formed at the observation term 68 Slight rain or drizzle and snow at the observation term 69 Moderate or heavy rain or drizzle and snow at the observation term 70 Slight, not freezing snow at the observation term, intermittent during preceding 71 Slight, not freezing snow at the observation term, continuous during preceding 72 Moderate, not freezing snow at the observation term, intermittent during preceding 73 Moderate, not freezing snow at the observation term, continuous during preceding 74 Heavy, not freezing snow at the observation term, intermittent during preceding 75 Heavy, not freezing snow at the observation term, continuous during preceding 76 Icy needles (with or without fog) at the observation term 77 Snow grains (with or without fog) at the observation term 78 Isolated star-like snow crystals (with or without fog) at the observation term 79 Icy rain at the observation term 80 Slight rain shower at the observation term 81 Moderate or heavy rain shower at the observation term 82 Violent rain shower at the observation term 83 Slight shower of rain and snow mixed at the observation term 84 Moderate or heavy shower of rain and snow mixed at the observation term 85 Slight snow shower at the observation term 86 Moderate or heavy snow shower at the observation term 87 Slight icy or snow pellets with or without rain or rain and snow mixed at the observation term 88 Moderate or heavy icy or snow pellets with or without rain or rain and snow mixed at the observation term 89 Slight hail with or without rain or rain and snow mixed at the observation term, not associated with thunder 90 Moderate or heavy hail with or without rain or rain and snow mixed at the observation term, not associated with thunder 91 Thunderstorm during the preceding and slight rain shower at the observation term 92 Thunderstorm during the preceding and moderate or heavy rain shower at the observation term 93 Thunderstorm during the preceding and slight snow, or rain showers and mixed snow shower or hail, icy or snow pellets at the observation term 94 Thunderstorm during the preceding and moderate or heavy snow, or rain showers and mixed snow shower or hail, icy or snow pellets at the observation term 95 Slight or moderate thunderstorm at the observation term without hail or icy/snow pellets, but with rain shower or/and snow shower at the observation term 96 Slight or moderate thunderstorm at the observation term with hail, icy or snow pellets at the observation term 97 Heavy thunderstorm at the observation term, without hail, but rain shower or/and snow shower at the observation term 98 Thunderstorm combined with dust - or sandstorm at the observation term, with or without precipitation 99 Heavy thunderstorm with hail, icy or snow pellets at the observation term 20 Drizzle (not freezing) or snow grains during the preceding 21 Rain (not freezing) during the preceding 22 Snow during the preceding (not falling as shower(s)) LEGMC The searching results explanations of meteorological data 5
Code 23 Rain and snow (icy pellets) during the preceding (not falling as shower(s)) 24 Freezing drizzle or freezing rain, those were forming a glaze during the preceding (not falling as shower(s)) 25 Rain shower during the preceding 26 Snow shower or with rain shower during the preceding 27 Hail or snow/icy pellets (with or without rain) during the preceding 28 Fog or icy fog and visibility less than 1 km during the preceding 29 Thunderstorm (with or without precipitation) during the preceding Code Past weather 1 and 2 0 Cloud amount 5 balls, clear sky between observation terms 1 Cloud amount changes from 5 to >5 balls between observation terms 2 Cloud amount >5 balls, overcast between observation terms 3 All type blowing snow (drifting snow, drifting blowing snow with or without snow) between observation terms. Dust - or sandstorm between observation terms 4 Fog or ice fog, or haze (visibility <1 km) between observation terms 5 Drizzle between observation terms 6 Rain between observation terms 7 Snow, snow grains, icy needles or icy rain, or rain and snow mixed between observation terms 8 Showers (snow shower, rain shower, snow or icy pellets, hail) between observation terms 9 Thunderstorm with or without precipitation between observation terms LEGMC The searching results explanations of meteorological data 6