This file describes the following data set: ALASKAN HISTORICAL CLIMATOLOGY NETWORK (HCN) SERIAL TEMPERATURE AND PRECIPITATION DATA [Carbon Dioxide Information Analysis Center Database (DB) 1004] T.R. Karl, R.G. Baldwin, M.G. Burgin, D.R. Easterling, R.W. Knight, and P.Y. Hughes (contributors) National Oceanic and Atmospheric Administration National Climatic Data Center Asheville, North Carolina 28801 CONTENTS I. Introduction II. Station inventory III. Description of monthly data file ("ak_hcn.dat") IV. Description of station history file ("ak_hcn.his") V. Data checks performed by CDIAC VI. References I. INTRODUCTION This database is a companion to the Historical Climatology Network (HCN) database for the contiguous United States [CDIAC Numeric Data Package (NDP) 019/R1]. The database contains monthly temperature (minimum, maximum, and mean) and total monthly precipitation data for 47 Alaskan stations. These data were derived from a variety of sources including the National Climatic Data Center archives, the state climatologist for Alaska, and published literature. The period of record varies by station. The longest record is for the Sitka Magnetic Observatory (beginning in 1828), and most records extend through 1990. Unlike the HCN database for the contiguous U.S., adjustments have not been made to these climate records for time-of-observation differences, instrument changes, or station moves. Because such occurrences may result in inhomogeneous time series, users of these data are urged to review the information given in the station history file in order to identify the stations most suitable for their particular applications. The data are contained in two files: (1) "ak_hcn.dat" (a 1.64 mB data file containing all four climate variables: monthly minimum, maximum, and mean temperatures, and total monthly precipitation); (2) "ak_hcn.his" (a 148 kB station history file). II. STATION INVENTORY St.# Station name Lat. Long. Elev. Record Pd. 26 Adak 51 53 N 176 39 W 17 1942-1990 230 Allakaket 66 34 N 152 40 W 600 1907-1982 280 Anchorage 61 10 N 150 01 W 114 1916-1990 352 Annette 55 02 N 131 34 W 109 1941-1990 363 Annex Creek 58 19 N 134 06 W 24 1917-1989 452 Attu 52 50 N 173 11 E 70 1917-1989 546 Barrow 71 18 N 156 47 W 31 1901-1990 558 Barter Island 70 07 N 143 40 W 39 1947-1988 754 Bethel 60 47 N 161 48 W 125 1923-1990 761 Bettles 66 55 N 151 31 W 644 1944-1990 770 Big Delta 64 00 N 145 44 W 1268 1937-1990 2102 Cold Bay 55 12 N 162 43 W 96 1942-1990 2177 Cordova 60 30 N 145 30 W 41 1909-1990 2607 Eagle 64 47 N 141 12 W 850 1899-1990 2968 Fairbanks 64 49 N 147 52 W 436 1929-1990 2988 Farewell 62 31 N 153 53 W 1499 1942-1976 3465 Gulkana 62 09 N 145 27 W 1572 1910-1990 3490 Haines 59 14 N 135 26 W 31 1925-1990 3655 Holy Cross 62 11 N 159 46 W 100 1893-1975 3665 Homer 59 38 N 151 30 W 67 1932-1990 3905 Iliamna 59 45 N 154 55 W 186 1920-1990 4094 Juneau No. 2 58 18 N 134 24 W 25 1881-1990 4100 Juneau AP 58 22 N 134 35 W 12 1943-1990 4546 Kenai 60 34 N 151 15 W 86 1882-1990 4590 Ketchikan 55 22 N 131 43 W 76 1910-1990 4766 King Salmon 58 41 N 156 39 W 49 1917-1990 4988 Kodiak 57 45 N 152 30 W 15 1869-1990 5076 Kotzebue 66 52 N 162 38 W 10 1897-1990 5519 Little Port Walter 56 23 N 134 39 W 14 1936-1990 5733 Matanuska AES 61 34 N 149 16 W 150 1917-1990 5769 McGrath 62 58 N 155 37 W 344 1939-1990 5778 McKinley Park 63 43 N 148 58 W 2070 1923-1990 6496 Nome 64 30 N 165 26 W 13 1906-1990 6586 Northway 62 58 N 141 56 W 1713 1942-1990 7783 Puntilla 62 06 N 152 45 W 1832 1942-1990 8118 St. Paul Island 57 09 N 170 13 W 22 1839-1990 8371 Seward 60 07 N 149 27 W 35 1908-1990 8419 Shemya 52 43 N 174 06 E 122 1943-1990 8494 Sitka Japonski FAA AP 57 04 N 135 21 W 36 1948-1990 8503 Sitka Magnetic Observatory 57 03 N 135 20 W 67 1828-1989 8976 Talkeetna 62 18 N 150 06 W 345 1918-1990 9014 Tanana 65 10 N 152 06 W 232 1904-1990 9564 Unalakleet 63 53 N 160 48 W 18 1941-1990 9641 Fairbanks - University Exp. Stn. 64 51 N 147 52 W 475 1904-1990 9686 Valdez 61 08 N 146 21 W 23 1909-1990 9919 Wrangell 56 29 N 132 22 W 44 1868-1990 9941 Yakutat 59 31 N 139 40 W 28 1917-1990 Note: Latitudes and longitudes are expressed in degrees and minutes. Elevations are expressed in whole feet above mean sea level. III. DESCRIPTION OF MONTHLY DATA FILE ("ak_hcn.dat") The data record consists of the following: Record position Field description 02-07 State/Station Identifier (comprised of a two-digit state code and a four-digit NWS Cooperative Station ID number) 09-12 Year 14 Data Element (where 1 = maximum temperature; 2 = minimum temperature; 3 = average temperature; 4 = precipitation) 16-132 Contains the 13 data values (12 monthly values and annual average), with flags; - All temperature values (maximum, minimum, and average) are expressed in units of tenths of degrees Fahrenheit; - Precipitation values are expressed in units of hundredths of inches; - Missing values are expressed as -9999; The data values and flag codes are formatted as follows: 16-20 January data value 21-24 Flags for January data value The monthly flags are expressed as 4 positions: - The first position gives an alpha-code to indicate between 1 to 9 days missing ("A","B","C",..."I"), or a code "." to indicate that the value is interpolated or estimated. [Note: For values from digital sources (e.g., second flag position = "0" or "1"), the days missing code will be an "I" to indicate between 1 to 9 days were missing from the monthly value; whereas, for non-digital sources, a days missing code of "I" means 9 days missing.]; - The second position indicates the data source (e.g., publication, manuscript, etc.); The codes and their meaning are as follows: 0 = NCDC Tape Deck 3200, Summary of the Day Element Digital File; 1 = NCDC Tape Deck 3220, Summary of the Month Element Digital File; 2 = Means Book--Smithsonian Institute, C.A. Schott (1876, 1881, up to 1931); 3 = Manuscript--Original National Climatic Data Records; 4 = CD--Climatological Data, published monthly by NCDC; 5 = Climate Record Book--for a description, see History of Climatological Record Books, U.S. Department of Commerce, Weather Bureau, U.S.G.P.O., 1960; 6 = Bulletin W--Summary of the Climatological Data for the United States by Section, by F.H. Bigelow, U.S. Weather Bureau, 1912; and Summary of the Climatological Data for the United States, (Bulletin W - 2nd ed.); 7 = LCD--Local Climatological Data, published monthly by NCDC; 8 = State climatologists - various sources; B = Professor Raymond Bradley--see Climatic Fluctuations of the Western United States During the Period of Instrumental Records, by Bradley, Barry, and Kiladis, Contribution No. 42, Department of Geography and Geology, University of Massachusetts, 1982; D = Dr. Henry Diaz--A compilation of data from Bulletin W, LCD, and NCDC Tape Deck 3220 (1983); G = Professor John Griffith--primarily from Climatological Data; Blank = computed value from two of three temperature elements; - The third position indicates trace ("T") amounts of precipitation (and is blank for temperature data values); - The fourth position is always blank. (Note: This flag position indicates whether value is an "outlier" -- but currently only used in US HCN, i.e., not for Alaska.) 25-29 February data value 30-33 Flags for February data value - (Data values with flags repeat for March through December) 124-128 Annual data value 129-132 Flags for Annual data value [Note: Flags for the annual data differ slightly from the monthly ones in that the days missing code (first flag position) will simply be an "I" to indicate "incomplete", if any monthly values had days missing.] IV. DESCRIPTION OF STATION HISTORY FILE ("ak_hcn.his") Note: In the context of the Alaskan Historical Climatology Network, the location of the temperature instrument defines the official station location. - - -HEADER RECORD- - - - - - - - - - - - - - - - - - - - - - - - - RECORD # OF POSITION CHAR CONFIGURATION DEFINITIONS & REMARKS 01-06 6 NUMERIC (values STATE & STATION NUMBER range from 010000 [First two positions to 919998) indicate the state code -- (see Appendix A for codes); last four indicate the NCDC Cooperative Substation ID#] 08-09 2 ALPHA STATE ABBREVIATION -- see Appendix A for codes 11-12 2 NUMERIC (values DIVISION NUMBER range from 01-10) 14-43 30 ALPHA-NUMERIC MOST CURRENT STATION NAME (condensed form of the station name and qualifier -- see Positions 84-122 of Data Record) 45-60 16 ALPHA COUNTY NAME [if a prior county location was known, the earlier name and date of change is given in the X-REFERENCE (Positions 62- 86 of the Header Record)] 62-86 25 ALPHA-NUMERIC X-REFERENCE -- Station # for another location to or from which the current station has moved, OR gives change in county name (e.g. "To 2337"; "From 2335"; "Cty = Buncombe, 9/1897"), OR Blank, if not applicable 87-232 146 BLANK - - - -DATA RECORD- - - - - - - - - - - - - - - - - - - - - - - - - RECORD # OF POSITION CHAR CONFIGURATION DEFINITIONS & REMARKS 01-06 6 NUMERIC (values STATE & STATION NUMBER range from 010000 [First two positions to 919998) indicate the state code -- (see Appendix A for codes); last four indicate the NCDC Cooperative Substation ID#] 08-17 10 NUMERIC (mm dd yyyy) BEGIN DATE -- comprised of: 08-09 2 Note: values are Month (mm = 01-12, 99) 11-12 2 separated by blanks Day (dd = 01-31, 99) 14-17 4 Year (yyyy = 1700-1991) 19-28 10 NUMERIC (mm dd yyyy) END DATE -- comprised of: 19-20 2 Note: values are Month (mm = 01-12, 99) 22-23 2 separated by blanks Day (dd = 01-31, 99) 25-28 4 Year (yyyy = 1700-1991) 30-44 15 NUMERIC (0, 1) SUSPECT FIELDS -- Positions equal to "1" indicate the data field(s) flagged by pre-key editor as suspect Position Data Field 30 1 Latitude 31 2 Longitude 32 3 Distance from Previous Location 33 4 Elevation 34 5 Distance from Post Office Location 35 6 Station Name 36 7 Qualifier 37 8 Instruments 38 9 Observation Times 39 10 Instrument Heights 40 11 Publications 41 12 Begin Date 42 13 End Date 43 14 Observer 44 15 Other Observers 46-51 6 NUMERIC LATITUDE (DEGREES/MINUTES) 46-48 3 S00-S90 Degrees, where "S" denotes sign: S = " " indicates North; S = "-" indicates South 50-51 2 00-59 Minutes 53-59 7 NUMERIC LONGITUDE (DEGREES/MINUTES) 53-56 4 S000-S180 Degrees, where "S" denotes sign: S = " " indicates West; S = "-" indicates East 58-59 2 00-59 Minutes 61-63 3 NUMERIC (values DISTANCE FROM PREVIOUS range from 000 to LOCATION (DPL) -- units 999) in miles to tenths unless Position 64 = "B", then the units are in "Blocks"; "999" = unknown distance [Note: Distances > 80 miles are flagged as suspect (refer to Position 32 of Data Record); "9xx" codes indicate distance value, exclusively for the temperature instrument; "8xx" codes indicate distance value, exclusively for precipitation.] 64 1 ALPHA (" ",B) UNITS INDICATOR FOR DPL -- "B" for Blocks; if blank, e.g., " " then units are in miles to tenths 65-67 3 ALPHA-NUMERIC DIRECTION FOR DPL -- codes for the 16-points are used: N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW; "999" = direction unknown; "000" indicates no change in direction -- except for some instances of precipitation only moves (see "8xx 000" example below). Examples of DPL Codes: (NOTE: the temperature instrument defines the official HCN location) CODE DEFINITION 999 999 Distance & direction unknown (the DPL is always missing in the first record for a new station); 015 NW Station moved 1.5 miles NW of previous location; 000 000 No change in either station OR instrument location 902 ESE Temperature instrument moved .2 miles ESE and precipitation instrument did not move; OR the precipitation instrument move was not equal to that of temperature instrument; 800 000 Precipitation instrument moved, but temperature instrument did not move (in more recent history entries the direction may be given rather than encoded as zeroes); 000 ESE Station moved <0.1 mi ESE of previous location; 999 NW Moved an unknown distance to a location NW of the previous location 69-73 5 NUMERIC ELEVATION (of ground at temperature site) -- given in whole feet above or below mean sea level 75-78 4 NUMERIC (values range DISTANCE FROM POST OFFICE from 0000 to 9999) (DPO) -- units are in miles to tenths unless Position 79 = "B", then units are given in "Blocks" (Note: For the continental U.S., "0999" is used to indicate missing DPO; for Alaska, however, "9999" is used for missing as it is quite possible for distances of more than 100 miles to lie between the station and the P.O.) 79 1 ALPHA (" ",B) UNITS INDICATOR FOR DPO -- "B" for Blocks; if blank, e.g., " " then units are in miles to tenths 80-82 3 ALPHA-NUMERIC DIRECTION FOR DPO -- codes for the 16-points are used: N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW; "999" = direction unknown; "000" indicates a location at the P.O. Examples of DPO Codes: CODE DEFINITION 0999 999 Distance & direction unknown 0015 NW Station 1.5 Miles NW of PO 0000 NW Station <0.1 Mile NW of PO 0000 999 Station <0.1 Mile from PO, direction unknown 0999 NW Station located an unknown distance to the NW of the PO 0000 000 Station located at PO 84-111 28 ALPHA STATION NAME (may include previous state/station number contained in parentheses, e.g., 4 to 6 characters) 113-122 10 ALPHA-NUMERIC QUALIFIER = description added to primary station name; e.g., ASHEVILLE 2N 124-159 36 NUMERIC (0, 1) INSTRUMENT INDICATOR -- Positions set equal to "1" indicate which instruments are on-site; otherwise "0" Position Instrument Mnemonic 124 1 Additional Instruments (wind, pressure, AI etc.) 125 2 Cotton Region Shelter (official) CRS 126 3 Dry-Bulb Thermometer DT 127 4 Class 'A' Evaporation Station EVA 128 5 Fischer-Porter Gage FP 129 6 Hygrothermograph HYTHG 130 7 Minimum Thermometer MN 131 8 Maximum Thermometer MX 132 9 Non-Recording River Gage NRIG 134 10 Non-Standard Rain Gage NSRG 135 11 Non-Standard Shelter NSS 136 12 Recording River Gage RRIG 137 13 Recording Rain Gage RRNG 138 14 Snow Density Gage SDE 139 15 Storage Gage SG 140 16 Standard Rain Gage SRG 141 17 Standard Shelter (official) SS 142 18 Thermograph TG 143 19 Digital Thermometer DGT 144 20 Tipping Bucket Gage TB 145 21 Other than Class A Evaporation station EVO 146 22 Maximum/Minimum Temperature System MMTS 147 23 Telemetry System TELSY 148 24 Hygrothermometer (type unknown) HYGRO 149 25 Hygrothermometer -- H06x series HY6 150 26 Hygrothermometer -- H08x series HY8 151 27 Shielded Fischer-Porter Gage SFP 152 28 Shielded Recording Rain Gage SRRNG 153 29 Shielded Storage Gage SSG 154 30 Shielded Standard Rain Gage SSRG 155 31 Shielded Tipping Bucket STB 156-159 32-36 Not assigned at present time (Note: Mnemonics are not included in the magnetic tape metadata; however, these abbreviations are commonly used in Historical Climatology Network printed products.) 161-164 4 ALPHA-NUMERIC OBSERVATION TIMES (OT) 161-162 2 Precipitation OT 163-164 2 Temperature OT The observation times are encoded to the nearest whole hour where known; in some instances, the observation may have been taken at a variable hour (e.g., sunrise or sunset) or according to a rotating seasonal schedule based upon agricultural needs. Examples: 01-24,99 Nearest Whole Hour; "99" for unknown SR Sunrise SS Sunset RS Rotating Schedule [in general, evening observations were taken during the winter months (Oct/Nov thru Apr/May) and morning observations taken during summer months or "crop season".] In "RS" instances, often two observations were taken during the summer -- usually between 5-7 am and again between 5-7 pm. In such 2 obs/day instances, it is unclear whether both elements are read twice, but recorded for a single hour; or (a more likely practice), the precipitation is recorded in the morning and temperature in the evening. At some sites (usually airports) a uniform schedule was in use, but the particular hour at which a particular element was observed was not specified. In these instances, the number of hours per day for which observations were taken is given. (Note: the number of hours must not be confused with synoptic observing schedules such as 3-hourly, 6-hourly, etc. ones at which observations are taken at intervals of every 3 hours, 6 hours, etc.) xxHR where xx indicates the number of hours for which the site took observations; An early practice regarding the observation times of temperature involved taking three readings (morning, afternoon, and evening or "tri-daily"). These readings were usually made at 7am, 2pm, and 9pm. A weighted average was computed in which the 9pm obs was summed twice and the total sum divided by 4 e.g., (7am + 2pm + 9pm + 9pm)/ 4. Note, in these instances, no precipitation observation time has been encoded. TRID indicates "tri-daily" temperature average The early editions of the Weather Bureau's reporting forms allowed space only for a single observing time to be entered. Later on revised forms specifically identified whether the observation time was for temperature or precipitation. In the instances where the forms were ambiguous with regard to the observing times of these elements, the OT is encoded as follows: 9xx9 where xx indicates the hour as listed for the observations; whether it is accurate for both temperature and precipitation is unknown. Examples of OT codes: SRSS Precipitation reading made at sunrise; temperature read at sunset; SS99 Precipitation read at sunset; temperature read at an unknown hour OR there is no temperature data available of that period of record; 0718 Precipitation read at 0700 (i.e., 7am); temperature read at 1800 (i.e., 6pm); 9079 Ambiguous form: 0700 was the only listed hour of observation -- unknown whether is for both temperature and precipitation; 06HR Station observed 6 hours/day; whether the average of these 6 observations is what was recorded or only a single hour was used is unclear; RSSS Precipitation readings made on a rotating schedule; temperatures read at sunset; TRID "Tri-daily" readings of temperature; no OT encoded for precipitation; 9918 Precipitation readings made at an unknown hour OR there is no precipitation data available for that period of record; temperature read at 1800. 166-167 2 ALPHA-NUMERIC HEIGHT OF PRECIPITATION (00-99, RF) INSTRUMENT ABOVE GROUND -- given in whole feet; "99" indicates missing; "98" indicates heights of 98 feet or greater; "RF" indicates a roof-top exposure; 168-169 2 ALPHA-NUMERIC HEIGHT OF TEMPERATURE (00-99, RF) INSTRUMENT ABOVE GROUND -- given in whole feet; "99" indicates missing; "98" indicates heights of 98 feet or greater; "RF" indicates a roof-top exposure; Examples of Instrument Height Codes: 0305 For a standard rain gage, the opening at top of the gage is mounted at 3 feet above the ground; and the thermometer (inside the shelter) is located at 5 feet above the ground; RF99 Precipitation gage is located on roof; thermometer height is unknown OR there is no temperature data available for that period of record; 9805 Precipitation gage is at least 98 feet above the ground; thermometer is mounted 5 feet above the ground; 171-186 16 NUMERIC (0, 1) PUBLICATION INDICATOR -- Positions equal to "1" indicate where station's data are published (see below) except when a "1" occurs in position 178 to indicate the data are unpublished; else is "0": Position Publication Mnemonic 171 1 Bulletin W BW 172 2 Combined Bulletin CB 173 3 Climatological Data CD 174 4 Daily River Stages DRS 175 5 Hydrologic Bulletin HB 176 6 Hourly Precipitation Data HPD 177 7 Snow Bulletin SB 178 8 NOT PUBLISHED NP 179 9 Report to the Chief of US Weather Bureau CWB 180 10 Monthly Weather Review MWR 181 11 State Publication SP 182 12 Local Climatological Data LCD 183 13 Bulletin Q (1870-1903) BQ 184 14 Storage Gage Precipitation Data (Western US) SGPD 185 15 Weekly Weather Review WWR 186 16 US Meteorological Yearbook MYB (Note: Mnemonics are not included in the magnetic tape metadata; however, these abbreviations are commonly used in the Historical Climatology Network printed products.) 188-233 46 ALPHA OBSERVERS NAME(S) 235-236 2 NUMERIC (00-99) NUMBER OF OBSERVERS -- this number gives either the number of observers used as observers by the listed agency or "corporate" observer (that is, "US Forest Service" may have actually been 5 different observers during the particular period of record) OR the number of additional known observers where to individually list multiple names would exceed the allotted space Distance conversions (1 city block = 0.1 mile; 1 rod = 16.5 feet) Feet = Mile Feet = Mile Fraction = Decimal 250 0.0 2376-2903 0.5 1/8 0.l 250-791 0.1 2904-3431 0.6 1/4 0.3 792-1319 0.2 3432-3959 0.7 3/8 0.4 1320-1847 0.3 3960-4487 0.8 1/2 0.5 1848-2375 0.4 4488-5015 0.9 3/4 0.8 State codes and abbreviations 01 AL Alabama 17 ME Maine 33 OH Ohio 02 AZ Arizona 18 MD Maryland 34 OK Oklahoma 03 AR Arkansas 19 MA Massachusetts 35 OR Oregon 04 CA California 20 MI Michigan 36 PA Pennsylvania 05 CO Colorado 21 MN Minnesota 37 RI Rhode Island 06 CT Connecticut 22 MS Mississippi 38 SC South Carolina 07 DE Delaware 23 MO Missouri 39 SD South Dakota 08 FL Florida 24 MT Montana 40 TN Tennessee 09 GA Georgia 25 NE Nebraska 41 TX Texas 10 ID Idaho 26 NV Nevada 42 UT Utah 11 IL Illinois 27 NH New Hampshire 43 VT Vermont 12 IN Indiana 28 NJ New Jersey 44 VA Virginia 13 IA Iowa 29 NM New Mexico 45 WA Washington 14 KS Kansas 30 NY New York 46 WV West Virginia 15 KY Kentucky 31 NC North Carolina 47 WI Wisconsin 16 LA Louisiana 32 ND North Dakota 48 WY Wyoming Planned additions to the US HCN: 49 -- Not Used 50 AK Alaska 51 HI Hawaii 66 PR Puerto Rico 67 VI Virgin Islands 91 Pacific Islands V. DATA CHECKS PERFORMED BY CDIAC The Carbon Dioxide Information Analysis Center (CDIAC) endeavors to provide quality assurance (QA) of all data before their distribution. To ensure the highest possible quality in the data, CDIAC conducts extensive reviews for reasonableness, accuracy, completeness, and consistency of form. While having common objectives, the specific form of these reviews must be tailored to each data set; this tailoring process may involve considerable programming efforts. The entire QA process is an important part of CDIAC's effort to assure accurate, usable data for researchers. The National Climatic Data Center (NCDC) quality controlled all stations, using outlier and areal edits, and also performed internal quality control checks. Although the data set sent by NCDC was in excellent condition, CDIAC still conducted QA checks on the Alaskan Historical Climatology Network (HCN) data and found some minor discrepancies. The following summarizes the QA checks performed on the Alaskan HCN data by CDIAC. A. The following arithmetic QA checks were performed on the Alaskan HCN data set for the four variables -- maximum temperature (max), minimum temperature (min), average temperature (avg), and precipitation (prec): 1) All values of max and min were checked for max < min; 2) All values of avg, max, and min were checked for avg > max or avg < min; 3) All values of avg, max, and min were checked for avg > ((min + max)/2) + 1, or avg < ((min + max)/2) - 1; 4) All values of prec were checked for prec < 0. Results: No erroneous values of the types described in (1) through (4) were found. B. Graphical QA checks were performed for each variable (max, min, avg, prec) for each of the 47 stations in the Alaskan HCN data set. These checks searched for any anomalous values which did not appear in the records of neighboring stations, abrupt changes in the pattern of values in a time series (as in, for example, a station move), etc. Results: 1) Station 2177 (Cordova) Maximum for Jan. 1969 was unusually low (15.2 F) for this site and could not be corroborated by data from a nearby station (data for station 9686, Valdez, were missing for this month). According to NCDC, the NCDC publication, "Climatological Data", lists two other stations (non-HCN) with temperatures in the teens: Cooper Lake Projects -- average max of 13.1 F Yakutat WB AP -- average max of 18.1 F 2) Station 3465 (Gulkana) Observations prior to 1921 appeared generally more erratic than those afterward [no observations are recorded for the period 1921-1941 (no station was in existence)]; values prior to 1921 show higher summer values for both maximum and minimum, and lower winter values for minimum; the minimum for Dec. 1917 is particularly low (-48.8 F). 3) Station 4590 (Ketchikan) Minimum value for Jan. 1916 (10.3 F) was unusually low for this site and could not be corroborated by data from a nearby station (records for nearby stations do not extend back to this date). According to NCDC, the "Climatological Data" publication was again referenced and this value agreed in comparison with other January 1916 values for stations within the climate division. 4) Station 9564 (Unalakleet) The record for this site is sporadic after Sep. 1978; maxima and minima after this time appear more variable than those before (specific high or low values appear in a general way to parallel those for a nearby station, 6496, Nome). C. The following QA checks were performed on the Alaskan HCN station history file: 1) State and station numbers were checked for accuracy and consistency; 2) Division/county names were checked for spelling and geographical accuracy; 3) Station names were checked for consistency and spelling; 4) Chronologies of station moves were checked for consistency; 5) Periods for which station history was given were checked for consistency with periods for which data records exist; 6) Information on suspect fields was noted and checked against the data fields in question; 7) Latitudes, longitudes, and elevations were checked for reasonableness, and changes were checked for consistency with station moves; 8) All fields were briefly checked for correct alignment and for obvious erroneous values. Results: 1) The stations listed below have station history information with earlier begin dates or later end dates than the meteorological data. No additional data can be located for these stations to complete the history time period. Station 280 (Anchorage) Station 5769 (McGrath) Station 558 (Barter Island) Station 8494 (Sitka-Japonski) Station 770 (Big Delta) Station 8976 (Talkeetna) Station 3465 (Gulkana) Station 9014 (Tanana) Station 4546 (Kenai) Station 9564 (Unalakleet) Station 4590 (Ketchikan) 2) Three sites have earlier had different station names than their current ones. The source of the station history information is the Weather Bureau 530-1 form. This form allows for the documentation of other names by which a station was "known as" (at least while that station occupied the given location). This convention was also used for the Alaskan HCN. Station 770 (Big Delta) was previously known as 'McCarty' Station 2607 (Eagle) was previously known as 'Ft. Egbert' Station 4766 (King Salmon) was previously known as 'Naknek' 3) Station 4766 (King Salmon) Prior to 1955, station name was 'Naknek'; station history record for 11 01 1955 - 09 26 1956 records changes in station name and in elevation, but no station move. 4) Station 4988 (Kodiak) a. Station history record for 03 01 1931 - 06 30 1941 gives the same latitude, longitude, and elevation (none of which are designated as suspect) as the preceding and following records, both of which are designated as having suspect latitude, longitude, and elevation. According to NCDC, latitude, longitude, and elevation were not originally reported for either the 08 01 1929 - 02 28 1931 period or the 07 01 1941 - 01 20 1942 period; therefore, these values were assumed to be the same as what was given for the 03 01 1931 - 06 30 1941 location, but flagged as suspect to differentiate accordingly. b. Station history record for 99 99 1954 - 09 08 1959 shows a change in elevation from the preceding record, but no station move is shown. According to NCDC, the latitude and longitude did not change (according to the station history reported in the "Local Climatological Data"). Apparently, the temperature instruments moved sometime during 1954, changing their elevation from 21 to 14 ft. The US HCN history's convention was to use the elevation of the ground at the temperature site. The amount of horizontal distance moved is unknown. 5) Station 7783 (Puntilla) Station history record for 05 01 1965 - 10 24 1971 shows a change in elevation from the preceding record, but no station move is shown. According to NCDC, the NWS station history form B-44 for this location does not report it as a move, although both the listed elevation and the distance/direction from the P.O. values did change. Many sites will not consider minor instrument relocations as "station moves". In this case, the amount of horizontal distance moved is unknown. 6) Station 8371 (Seward) a. Station history record for 02 03 1942 - 09 17 1944 shows a station move of 1.3 mi. NNW from the preceding record, but no change in latitude or longitude is shown. b. Station history record for 11 05 1965 - 07 01 1970 shows a change in elevation from the preceding record, but no station move is shown. According to NCDC, the change in elevation reported was due to a re-survey of the station site. There was no move on 11 05 1965. 7) Station 8503 (Sitka Magnetic Observatory) Station history record for 04 01 1942 - 06 01 1951 shows a station move of 1.0 mi. NE from the preceding record, but no change in latitude or longitude is shown. 8) Station 9564 (Unalakleet) Station history record for 06 22 1967 - 10 25 1976 shows a change in elevation from the preceding record, but no station move is shown. According to NCDC, the change in elevation reported was due to a re-survey of the station site. There was no move on 06 22 1967. 9) Station 9919 (Wrangell) a. Station history record for 01 16 1927 - 11 30 1930 shows a station move of 1.9 mi. SE from the preceding record, but no change in latitude or longitude is shown. b. Station history record for 11 30 1930 - 02 15 1941 shows a station move of 2.0 mi. NNW from the preceding record, but no change in latitude or longitude is shown. VI. REFERENCES Baker, D.G., and D.L. Ruschy. 1989. Temperature measurements compared. The State Climatologist. Fall 1989, V. 13, Issue 3, NOAA/NESDIS/NCDC. Barnett, T.P. 1985. Long-term changes in precipitation patterns. In M.C. MacCracken and F.M. Luther (eds.), Detecting the Climate Effects of Increasing Carbon Dioxide. DOE/ER-0235. U.S. Department of Energy, Washington, D.C. Diaz, H.F., and R.G. Quayle. 1980. The climate of the United States since 1895: Spatial and temporal changes. Monthly Weather Review 108:249-266. Jones, P.D., S.C.B. Raper, R.S. Bradley, H.F. Diaz, P.M. Kelly, and T.M.L. Wigley. 1986. Northern Hemisphere surface air temperature variations 1851-1984. Journal of Climate and Applied Meteorology 25(2):161-179. Karl. T.R. 1985. Perspective on climate change in North America during the twentieth century. Physical Geography 6:207-229. Karl, T.R., and C.N. Williams, Jr. 1987. An approach to adjusting climatological time series for discontinuous inhomogeneities. Journal of Climate and Applied Meteorology 26:1744-1763. Karl, T.R., G. Kukla, and J. Gavin. 1984. Decreasing diurnal temperature range in the United States and Canada from 1941 through 1980. Journal of Climate and Applied Meteorology 23:1489-1504. Karl, T.R., C.N. Williams, Jr., P.J. Young, and W.M. Wendland. 1986. A model to estimate the time of observation bias associated with monthly mean maximum, minimum, and mean temperatures for the United States. Journal of Climate and Applied Meteorology 25:145-160. Karl, T.R., H.F. Diaz, and G. Kukla. 1988. Urbanization: Its detection and effect in the United States climate record. Journal of Climate 1:1099-1123. Karl, T.R., C.N. Williams, Jr., and F.T. Quinlan. 1990. United States Historical Climatology Network (HCN) serial temperature and precipitation data. NDP-019/R1. Carbon Dioxide Information Analysis Center. Oak Ridge National Laboratory, Oak Ridge, Tennessee. Thompson, L.M. 1975. Weather variability, climatic change, and grain production. Science 188:535-541. Vinnikov, K. Ya., G.V. Gruza, V.F. Zakharov, A.A. Kovyneva, and E. Ya. Rankova. 1980. Contemporary variations of the northern hemisphere climate. Meteorologiya i Gidrologiya 6:5-17. Vinning, K.C., and J.F. Griffiths. 1985. Climatic variability at ten stations across the United States. Journal of Climate and Applied Meteorology 24:363-370. Wigley, T.M.L., J.K. Angell, and P.D. Jones. 1985. Analysis of the temperature record. In M.C. MacCracken and F.M. Luther (eds.), Detecting the Climate Effects of Increasing Carbon Dioxide. 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