Evaporation records at Rio Grande were discontinued on September 12, 1914. The Gatun wind station was removed from the old administration building on October 5, 1914, to its present location on the tower of the hydrographic station about 100 yards south of the Gatun Railroad station. The Colon meteorological office was moved from the first to the second floor of the Panama Railroad office building on October 28, 1914, with very little change in instrument exposure. The tide registers at Colon were moved from Dock No. 1 to Dock No. 2, on December 9, 1914, and from Dock No. 2 to the present location on Dock No. 9, Cristobal, on May 1, 1915. The rainfall station at Porto Bello was discontinued on September 1, 1914, owing to the abandonment of the American settlement. PRECIPITATION. The rainfall for the year 1914 was deficient at all stations except Juan Mina, El Vigia, and Colon. The annual totals ranged from 132.70 inches at Colon to 64.48 inches at Balboa Heights. The average precipitation over the Pacific section was 68.02 inches, 86.14 inches over the central section, and 115.54 inches over the Atlantic section. The 1914 dry season rainfall amounted to but 6 per cent of the annual total in the Pacific section; 4 per cent in the central section; and 7 per cent in the Atlantic section. October was the rainiest month, in the Atlantic section and the northern part of the central section; May was the rainiest month in the southern part of the central section and northern part of the Pacific section, while on the Pacific coast November was the month during which the most rainfall occurred. March was the month of least rainfall in all sections. The maximum 24-hour rainfall recorded during the year was 6.85 inches at Gatun, on August 12 and 13, most of which fell between the hours of 2 and 4 p. m. on the 12th. Daily quantities in excess of 4 inches were recorded as follows: The rainfall during the first four months of 1915 was generally above normal, the excess occurring in the dry-season months-January to April, inclusive. Two storms, or so-called "northers," during the period from February 9 to 11, inclusive, and from April 3 to 5, inclusive, influenced the total amount of rainfall to a great extent, the fall during these periods being general over the Isthmus, although greater over the Atlantic than over the other sections. On February 10 and 11 the precipitation at Colon in 24 consecutive hours was 7.94 inches, and a fall of 8.30 inches occurred in 24 consecutive hours at Gatun on April 3 and 4. This exceeded the maximum 24hour precipitation on the Isthmus during the wet season of 1914. The greatest amount of precipitation on record for 24 consecutive hours is 10.86 inches at Porto Bello on December 28 and 29, 1909. The rainfall since the beginning of the rainy season has been generally deficient, the deficiency being well marked during the month of May. The June rainfall at Balboa and Balboa Heights was the lowest on record for a period of 19 and 18 years, respectively. Monthly records for 1914, 1915, and the station averages, are represented in Table No. 1, while the maximum rainfall of record for periods of 5 minutes, 1 hour, and 24 hours, at stations equipped with automatic registers, is shown in Table No. 2. TEMPERATURE. The average air temperature for the year 1914 was slightly above normal. March was the month of highest mean temperature, and October the month of lowest mean temperature on the Pacific coast, while on the Atlantic coast the highest mean temperature occurred in July and the lowest in September. The means and extremes in air temperature for the year 1914, at the two first-class stations, are given in the following table: The absolute maximum and minimum temperature for the years of record are shown below, revised to June 30, 1915: NOTE. The lowest temperature of record on the Isthmus is 59° F., observed at Bas Obispo on Feb. 9, 1907. The maximum temperature record of 97° F., at Balboa Heights (then Ancon) was equalled at the Naos Island station on Feb. 13, 1906. Temperature continued generally above normal during the first six months of 1915. Monthly temperature records and other meteorological data for the year 1914 at the two first-class stations, and at the Culebra station during the eight months of record, are presented in Tables Nos. 3, 4, and 5. WINDS. The wind movement over the Canal Zone for the year 1914 was generally above the normal. North and northwest winds prevailed. March was the month of greatest wind movement and October the month of least wind movement at all stations except Gatun, where the minimum movement occurred in December. See Plate No. 79, Wind Roses for the year 1914, Wet and Dry Seasons, and Plate No. 80, Wind Roses, Dry Season 1915. The following table revised to June 30, 1915, shows the maximum wind velocities of record at the first-class stations: The maximum wind velocity at Colon occurred during the storm, or so-called "Norther," of April 3 to 5, 1915, the highest velocity heretofore being 40 miles from the south on July 16, 1908. ATMOSPHERIC PRESSURE. The mean atmospheric pressure for the year 1914 was slightly below the normal. January was the month of highest mean pressure at both stations, while the lowest mean pressure occurred in July on the Pacific coast, and in December on the Atlantic coast. RELATIVE HUMIDITY. The mean relative humidity of the atmosphere in 1914 was practically normal at both stations. On the Atlantic coast September was the month of highest average humidity and February the month of lowest average humidity, while on the Pacific coast the months of highest and lowest average humidity were November and March, respectively. CLOUDINESS. The average daytime cloudiness for the year 1914 was practically normal on the Atlantic coast, and slightly below the average on the Pacific coast. September was the month of heaviest cloudiness at both stations, while the least average cloudiness occurred in March on the Atlantic coast, and in january on the Pacific coast. EVAPORATION. The weather conditions during the year 1914 again favored a high rate of evaporation. Owing to the moving of the station at Ancon to Balboa Heights, evaporation records at the latter place for the month of October were lost, but the 11 months total exceeded the station average. At Gatun the annual total was above the normal, while at Colon the yearly amount exceeded all previous records. Evaporation during the first six months of 1915 has been above normal at Balboa Heights and Colon, Basslightly below the average at Gatun. The monthly records are given in Table No. 6. The total evaporation for the year 1914, together with the station averages, are presented in the following table: Only one fog was observed during the year 1914 at either coast station, but night and early morning fogs were quite numerous over the interior. Over the Gaillard Cut section of the canal there were 139 days on which fogs were observed. The greatest number of fogs occurred here during the month of October, and the least number during the month of March. Practically all fogs lifted or were dissipated by 8.30 a. m. SEA TEMPERATURE. The average surface temperature of the sea water was approximately 1° F. above normal on the Atlantic coast, and 1° F. below the normal on the Pacific coast. The means and extremes for the year 1914 are given in the following table: Tide registers were continued in operation at Balboa and Colon. The tidal extremes for the years of record at these stations are given below (length of record, 8 years), table revised to June 30, 1915: 1 For consecutive tides. 2 One tidal fluctuation often entirely absent at Colon. Tidal conditions on the Atlantic and Pacific coasts for the year 1914 are shown in Table No. 7. SEISMOLOGY. Fourteen seismic disturbances were recorded at Ancon or Balboa Heights during the fiscal year 1914-15. Of these, four were of comparatively local origin-less than 200 miles distant. The remainder were tremors from shocks of comparatively distant origin. Three of the shocks were of sufficient intensity to be generally felt over the Isthmus. The intensity of al the disturbances ranged from I to III, Rossi-Forel scale. No damage resulted from any of the shocks. A complete list of seismic disturbances recorded at Balboa Heights during the fiscal year 1914-15 is given in Table No. 8. The following charts and tables accompany the meteorological section of this report: Plate No. 89 Table No. 1 Table No.-2: Table No. 3. Table No. 4. Monthly rainfall on the Isthmus of Panama. Maximum rainfall in the Canal Zone. Monthly meteorological data, Balboa Heights, year 1914. Monthly meteorological data, Culebra, year 1914. Table No. 6. Monthly evaporation, Canal Zone, 1914, 1915, and averages. Table No. 8. Seismograph records, Balboa Heights, fiscal year 1914-15. TABLE 1.-Monthly rainfall on Isthmus of Panama, 1914–15, and station averages. Stations. [Value in inches.] Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct Nov. Dec. Year. 1914.. .44 .38 .02 1915. Average, 4 years. 1.06 Alhajuela: 3.43 .20 1.01 8.40 12.51 9.72 12.26 17.10 20. 19 8.26 6. 15 77.35 92.11 1.24 12.09 10.99 8.78 11.63 12.04 13.07 12.44 4.76 88.52 1 Formerly Ancon, station moved to Balboa Heights Oct. 1, 1914. TABLE 1.-Monthly rainfall on Isthmus of Panama, 1914-15, and station averages— Continued. [Value in inches.] Stations. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Year. Frijoles: 1914.. 1915. .69 11.56 10.71 10.54 0.81 1.33 0.40 2.95 14.33 13.05 4.06 9.66 10.55 18.99 8.83 6.94 91.90 3.63 5.66 1.55 Gatun: .96 3.26 10.91 12.64 Brazos Brook: 4.62 92.18 9.86 16.22 20.76 11.97 125.51 1.21 7.33 13.77 15.84 10.30 14.70 13.28 22.30 16.61 .96 12.17 6.41 16.48 4.28 15.15 10.95 14.14 12.57 5.17 121.75 2.67 Colon: Average, 8 years. 3.46 Average, 44 years 3.97 1.47 1.63 4.05 12.77 13.38 16.22 15.10 12.52 14.56 21.66 12.10 129.43 NOTE.-Station averages do not include records for the year 1915. TABLE 2.-Maximum rainfall in Canal Zone, Oct. 1, 1905, to June 30, 1915. [Value in inches.] 3.94 13.88 15.42 15.55 14.94 11.80 16.28 23.42 13.00 136.73 .91 4.12 17.76 16.30 10.74 16.01 14.80 22.16 18.35 8.88 132.70 1.71 10.42 7.75 16.01 No automatic record on this date; total for 24 hours ending at noon. Automatic gauge discontinued May 9, 1914. Station closed Aug. 31, 1914. Approximate; automatic record indistinct, due to unusually excessive rate of fall. 7 Station closed January, 1912. NOTE.-Dates in parentheses opposite station names refer to installation of automatic register. |