NOTES FOR DC02D COMPLETED ON 01/12/2022 ____________________________________________________________________________________________ ____________________________________________________________________________________________ DATA FILE Byte Location , Byte Size , Explanation -------------------------------------------------------------------------------------------- 1-2 ,2 , Record identifier - dc 4-9 ,6 , Bureau of Meteorology Station Number. 11-20 ,10 , Year month day in YYYY,MM,DD format. 22-27 ,6 , Precipitation in the 24 hours before 9am (local time). In mm. 29 ,1 , * Quality of precipitation value. 31-32 ,2 , Number of days of rain within the days of accumulation. 34-35 ,2 , Accumulated number of days over which the precipitation was measured. 37-42 ,6 , Precipitation since last observation, at 00 hours Local Time. In mm. 44 ,1 , * Quality of precipitation since last observation value, at 00 hours Local Time. 46-51 ,6 , Precipitation since last observation, at 03 hours Local Time. In mm. 53 ,1 , * Quality of precipitation since last observation value, at 03 hours Local Time. 55-60 ,6 , Precipitation since last observation, at 06 hours Local Time. In mm. 62 ,1 , * Quality of precipitation since last observation value, at 06 hours Local Time. 64-69 ,6 , Precipitation since last observation, at 09 hours Local Time. In mm. 71 ,1 , * Quality of precipitation since last observation value, at 09 hours Local Time. 73-78 ,6 , Precipitation since last observation, at 12 hours Local Time. In mm. 80 ,1 , * Quality of precipitation since last observation value, at 12 hours Local Time. 82-87 ,6 , Precipitation since last observation, at 15 hours Local Time. In mm. 89 ,1 , * Quality of precipitation since last observation value, at 15 hours Local Time. 91-96 ,6 , Precipitation since last observation, at 18 hours Local Time. In mm. 98 ,1 , * Quality of precipitation since last observation value, at 18 hours Local Time. 100-105 ,6 , Precipitation since last observation, at 21 hours Local Time. In mm. 107 ,1 , * Quality of precipitation since last observation value, at 21 hours Local Time. 109-113 ,5 , Evaporation in 24 hours before 9am (local time). In mm. 115 ,1 , * Quality of evaporation in 24 hours before 9am (local time). 117-118 ,2 , Days of accumulation for evaporation. 120-124 ,5 , Maximum temperature in 24 hours after 9am (local time). In Degrees C. 126 ,1 , * Quality of maximum temperature in 24 hours after 9am (local time). 128-129 ,2 , Days of accumulation of maximum temperature. 131-135 ,5 , Minimum temperature in 24 hours before 9am (local time). In Degrees C. 137 ,1 , * Quality of minimum temperature in 24 hours before 9am (local time). 139-140 ,2 , Days of accumulation of minimum temperature. 142-146 ,5 , Air temperature observation at 00 hours Local Time. In Degrees C. 148 ,1 , * Quality of air temperature observation at 00 hours Local Time. 150-154 ,5 , Air temperature observation at 03 hours Local Time. In Degrees C. 156 ,1 , * Quality of air temperature observation at 03 hours Local Time. 158-162 ,5 , Air temperature observation at 06 hours Local Time. In Degrees C. 164 ,1 , * Quality of air temperature observation at 06 hours Local Time. 166-170 ,5 , Air temperature observation at 09 hours Local Time. In Degrees C. 172 ,1 , * Quality of air temperature observation at 09 hours Local Time. 174-178 ,5 , Air temperature observation at 12 hours Local Time. In Degrees C. 180 ,1 , * Quality of air temperature observation at 12 hours Local Time. 182-186 ,5 , Air temperature observation at 15 hours Local Time. In Degrees C. 188 ,1 , * Quality of air temperature observation at 15 hours Local Time. 190-194 ,5 , Air temperature observation at 18 hours Local Time. In Degrees C. 196 ,1 , * Quality of air temperature observation at 18 hours Local Time. 198-202 ,5 , Air temperature observation at 21 hours Local Time. In Degrees C. 204 ,1 , * Quality of air temperature observation at 21 hours Local Time. 206-208 ,3 , -*- Relative humidity for observation at 00 hours Local Time. In percentage %. 210 ,1 , * Quality of relative humidity for observation at 00 hours Local Time. 212-214 ,3 , -*- Relative humidity for observation at 03 hours Local Time. In percentage %. 216 ,1 , * Quality of relative humidity for observation at 03 hours Local Time. 218-220 ,3 , -*- Relative humidity for observation at 06 hours Local Time. In percentage %. 222 ,1 , * Quality of relative humidity for observation at 06 hours Local Time. 224-226 ,3 , -*- Relative humidity for observation at 09 hours Local Time. In percentage %. 228 ,1 , * Quality of relative humidity for observation at 09 hours Local Time. 230-232 ,3 , -*- Relative humidity for observation at 12 hours Local Time. In percentage %. 234 ,1 , * Quality of relative humidity for observation at 12 hours Local Time. 236-238 ,3 , -*- Relative humidity for observation at 15 hours Local Time. In percentage %. 240 ,1 , * Quality of relative humidity for observation at 15 hours Local Time. 242-244 ,3 , -*- Relative humidity for observation at 18 hours Local Time. In percentage %. 246 ,1 , * Quality of relative humidity for observation at 18 hours Local Time. 248-250 ,3 , -*- Relative humidity for observation at 21 hours Local Time. In percentage %. 252 ,1 , * Quality of relative humidity for observation at 21 hours Local Time. 254-258 ,5 , ***- Speed of maximum wind gust in km/h. 260 ,1 , * Quality of maximum gust speed. 262-266 ,5 , ***- Direction of maximum wind gust in degrees. 268 ,1 , * Quality of maximum gust direction. 270-273 ,4 , ***- Time of maximum wind gust in HHMI 24 hour mode. 275 ,1 , * Quality of maximum wind gust time. 277-281 ,5 , ***- Wind speed at 00 hours Local Time, measured in km/h. 283 ,1 , * Quality of wind speed at 00 hours Local Time. 285-289 ,5 , ***- Wind speed at 03 hours Local Time, measured in km/h. 291 ,1 , * Quality of wind speed at 03 hours Local Time. 293-297 ,5 , ***- Wind speed at 06 hours Local Time, measured in km/h. 299 ,1 , * Quality of wind speed at 06 hours Local Time. 301-305 ,5 , ***- Wind speed at 09 hours Local Time, measured in km/h. 307 ,1 , * Quality of wind speed at 09 hours Local Time. 309-313 ,5 , ***- Wind speed at 12 hours Local Time, measured in km/h. 315 ,1 , * Quality of wind speed at 12 hours Local Time. 317-321 ,5 , ***- Wind speed at 15 hours Local Time, measured in km/h. 323 ,1 , * Quality of wind speed at 15 hours Local Time. 325-329 ,5 , ***- Wind speed at 18 hours Local Time, measured in km/h. 331 ,1 , * Quality of wind speed at 18 hours Local Time. 333-337 ,5 , ***- Wind speed at 21 hours Local Time, measured in km/h. 339 ,1 , * Quality of wind speed at 21 hours Local Time. 341-345 ,5 , ***- Wind direction at 00 hours Local Time, measured in degrees. 347 ,1 , * Quality of wind direction at 00 hours Local Time. 349-353 ,5 , ***- Wind direction at 03 hours Local Time, measured in degrees. 355 ,1 , * Quality of wind direction at 03 hours Local Time. 357-361 ,5 , ***- Wind direction at 06 hours Local Time, measured in degrees. 363 ,1 , * Quality of wind direction at 06 hours Local Time. 365-369 ,5 , ***- Wind direction at 09 hours Local Time, measured in degrees. 371 ,1 , * Quality of wind direction at 09 hours Local Time. 373-377 ,5 , ***- Wind direction at 12 hours Local Time, measured in degrees. 379 ,1 , * Quality of wind direction at 12 hours Local Time. 381-385 ,5 , ***- Wind direction at 15 hours Local Time, measured in degrees. 387 ,1 , * Quality of wind direction at 15 hours Local Time. 389-393 ,5 , ***- Wind direction at 18 hours Local Time, measured in degrees. 395 ,1 , * Quality of wind direction at 18 hours Local Time. 397-401 ,5 , ***- Wind direction at 21 hours Local Time, measured in degrees. 403 ,1 , * Quality of wind direction at 21 hours Local Time. 405 ,1 , Total cloud amount at 00 hours Local Time, in eighths. 407 ,1 , * Quality of total cloud amount at 00 hours Local Time. 409 ,1 , Total cloud amount at 03 hours Local Time, in eighths. 411 ,1 , * Quality of total cloud amount at 03 hours Local Time. 413 ,1 , Total cloud amount at 06 hours Local Time, in eighths. 415 ,1 , * Quality of total cloud amount at 06 hours Local Time. 417 ,1 , Total cloud amount at 09 hours Local Time, in eighths. 419 ,1 , * Quality of total cloud amount at 09 hours Local Time. 421 ,1 , Total cloud amount at 12 hours Local Time, in eighths. 423 ,1 , * Quality of total cloud amount at 12 hours Local Time. 425 ,1 , Total cloud amount at 15 hours Local Time, in eighths. 427 ,1 , * Quality of total cloud amount at 15 hours Local Time. 429 ,1 , Total cloud amount at 18 hours Local Time, in eighths. 431 ,1 , * Quality of total cloud amount at 18 hours Local Time. 433 ,1 , Total cloud amount at 21 hours Local Time, in eighths. 435 ,1 , * Quality of total cloud amount at 21 hours Local Time. 437 ,1 , # symbol, end of record indicator. ACCUMULATED REPORTS ___________________ Daily elements are reported at 9am, however many Australian observers do not report over a weekend or holiday. In this case they may accumulate rainfall and other elements such as maximum temperature. Thus the rainfall total reported on a Monday morning may be the total since the previous Friday, not just for the last 24 hours. Similarly, the maximum temperature may be the highest over a period of 2 or 3 days. Where this happens, the 'days of accumulation' field gives the number of days involved. -*- MOISTURE EQUATIONS ______________________ The following formulas have been used: Vapour pressure = exp (1.8096 + (17.269425 * Dew_Point)/(237.3 + Dew_Point)) Saturated Vapour pressure = exp (1.8096 + (17.269425 * Air_Temperature)/(237.3 + Air_Temperature)) Relative Humidity = Vapour pressure / Saturated vapour pressure * 100 Relative humidity (RH) is obtained either from measurements by an electronic relative humidity sensor or derived via complex equations from wet and dry bulb temperature observations. There can be slight differences between RH values measured directly by a relative humidity sensor and those derived using equations. Typically these differences are less than 1%. The uncertainty associated with RH data increases at the extremes. That is, in very dry air as RH approaches 0%, and in very humid conditions as RH approaches 100%. There are some occasions when reported RH values may slightly exceed 100%. In these instances you should consider the value to be 100%. * QUALITY FLAG DESCRIPTIONS ___________________________ Y: quality controlled and acceptable N: not quality controlled W: quality controlled and considered wrong S: quality controlled and considered suspect I: quality controlled and inconsistent with other known information X: no quality information available ***- WIND MEASUREMENTS ______________________ 1. The Bureau's wind measurements are designed to satisfy weather and climate monitoring needs. The Bureau's current uncertainty tolerances for wind speed measurements are +/- 10% of the wind speed for wind speeds greater than 10 m/s and +/- 1 m/s for wind speeds at or below 10 m/s. As equipment is modernised at observing sites, the Bureau's continuous improvement requirement is to ensure that no change in equipment or algorithm results in wind speed measurements with a higher uncertainty, and where possible decreases uncertainty. 2. In 2010, with the incorporation of new monitoring equipment with improved algorithms to convert raw outputs into wind speed, a step change downwards in the wind speed measurements has occurred of the order of 0.5 m/s at some sites. Investigations have not lead to any evidence that the wind speed measurements using the Telvent AWS are outside the Bureau's uncertainty tolerance. We are confident that the new measurements provide a better estimate of the true wind speed, and may ultimately result in revised and improved uncertainty tolerances for Bureau wind speed measurements of both the past and future. We are now investigating ways to apply this knowledge to the past wind record. GAPS AND MISSING DATA _____________________ Very few sites have a complete unbroken record of climate information. A site may have been closed, reopened, upgraded to a full weather site or downgraded to a rainfall only site during its existence causing breaks in the record for some or all elements. Some gaps may be for one element due to a damaged instrument, others may be for all elements due to the absence or illness of an observer. INSTUMENTS AND OBSERVATIONAL PRACTICES ______________________________________ Historically a nearby site (within about 1 mile in earlier days) may have used the same site number. There may have been changes in instrumentation and/or observing practices over the period included in a dataset, which may have an effect on the long-term record. In recent years many sites have had observers replaced by Automatic Weather Stations, either completely or at certain times of the day. TIME ____ For a part of the year some Australian States adopt Daylight Savings Time (DST), and observers continue to take observations according to the local clock. Times provided with this data are Local Time, unless otherwise noted. Care needs to be taken when comparing values from year to year or month to month, because for some elements the effect of one hour can be marked, for example air temperature often rises sharply between 8am and 9am. Daylight Savings has been used in many Australian states since 1973. The changeovers occur almost always in October and March, but exact dates vary from State to State and year to year. More information can be found at: http://www.bom.gov.au/climate/averages/tables/daysavtm.shtml ROUNDING ________ The primary way of sending current weather information around the world is via a coded message known as a SYNOP. This message only allows some measurements to be sent as rounded values. Once manuscript records have been sent in many of these values are typed in with greater precision (normally to one decimal place). This usually occurs within a few months. If consecutive values all have a zero in the decimal place, then it is almost certain that rounding was used earlier. A new type of message format is progressively being introduced to overcome this situation. COPYRIGHT _________ The copyright for any data is held in the Commonwealth of Australia and the purchaser shall give acknowledgement of the source in reference to the data. Apart from dealings under the copyright Act, 1968, the purchaser shall not reproduce, modify or supply (by sale or otherwise) these data without written permission. Enquiries should be made to the Bureau of Meteorology, PO Box 1289K, Melbourne 3001, marked to the attention of SRDS. LIABILITY _________ While every effort is made to supply the best data available this may not be possible in all cases. We do not give any warranty, nor accept any liability in relation to the information given, except that liability (if any), that is required by law. IF DATA IS NOT AS REQUESTED ___________________________ If the data provided are not as requested, the data will be repeated at no extra cost, provided that: a) the Bureau is notified within 60 days. b) the printout/disc/data file is returned to the Bureau for checking. c) there has been a fault or error in providing the data. Where there has been no fault or error of provision, the cost involved in requested corrective action such as resending the data or providing alternative sites will be charged for as necessary. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SITE DETAILS FILE This file contains the details for the current site or are those which applied when the site was closed. Many sites have been moved, downgraded, upgraded etc over the years. Byte Location , Byte Size , Explanation -------------------------------------------------------------------------------------------- 1-2 ,2 , Record identifier - st 4-9 ,6 , Bureau of Meteorology Station Number. 11-14 ,4 , Rainfall district code 16-55 ,40 , Station Name. 57-63 ,7 , Month/Year site opened. (MM/YYYY) 65-71 ,7 , Month/Year site closed. (MM/YYYY) 73-80 ,8 , Latitude to 4 decimal places, in decimal degrees. 82-90 ,9 , Longitude to 4 decimal places, in decimal degrees. 92-106 ,15 , Method by which latitude/longitude was derived. 108-110 ,3 , State. 112-117 ,6 , Height of station above mean sea level in metres. 119-124 ,6 , Height of barometer above mean sea level in metres. 126-130 ,5 , WMO (World Meteorological Organisation) Index Number. 132-135 ,4 , First year of data supplied in data file. 137-140 ,4 , Last year of data supplied in data file. 142-144 ,3 , Percentage complete between first and last records. 146-148 ,3 , Percentage of values with quality flag 'Y'. 150-152 ,3 , Percentage of values with quality flag 'N'. 154-156 ,3 , Percentage of values with quality flag 'W'. 158-160 ,3 , Percentage of values with quality flag 'S'. 162-164 ,3 , Percentage of values with quality flag 'I'. 166 ,1 , # symbol, end of record indicator. LATITUDES AND LONGITUDES ________________________ Latitudes and longitudes are given to 4 decimal places, but in many cases will not be accurate to 4 decimal places. This is because in the early days the positions of stations were estimated from maps. Gradually the network of open stations is being checked (and if necessary corrected) using GPS (Global Positioning System). The method used is given in the site details file. WMO INDEX NUMBER ________________ This is the number assigned to a site that makes international weather reports every day. The number is not actively used in the climate archive, and only a few hundred such numbers are assigned at any time. These are not perpetual but may be reassigned where a site no longer makes the international reports (synops); thus a particular number cannot be regarded as unique and exclusive to any particular site. PERCENTAGE INFORMATION ______________________ In some cases the percentage completeness will be overestimated. This will occur if the database has incomplete information about the element being selected. In cases where several elements are selected, rows with a least one of the elements available are considered complete. Where only a limited amount of data is available and the percentage completeness is less than 0.5%, an "*" has been used. An "*" is also used if the percentage of values with a particular quality flag is non zero and less than 0.5%.