Weather-recording instruments pen-bit tuning tips

Study:

Brief summary of the various self-recording meteorological instruments to adjust the standard pen position, and stressed the variety of self-recording instrument in adjusting document bits must pay attention to several issues.

Keywords: self-recording meteorological instruments; pen position adjustment; standards; skills

Current weather stations measuring temperature, humidity, pressure and manual observation methods are 2 kinds of automatic measurement equipment. Using thermometers measure temperature, humidity, wet and dry bulb thermometer test, test pressure mercury barometer, rain gauge measured precipitation, through the time of artificial the observed values as the measured value [1]. The thermometer, hair hygrometer, barometer empty box, siphon rain gauge is automatically recorded, respectively, temperature, relative humidity, air pressure, precipitation continuous change instruments, collectively referred to as self-recording apparatus , self-recording from the instrument can be obtained at any time record temperature, relative humidity, air pressure, precipitation changes, and extreme values (highest and lowest values) and the appearance time, measured by self-recording instrument referred to as self-value write value [2]. measured value and self-recording is often some difference between the values, but should be within reasonable limits. If you exceed a certain range, it should promptly identify the causes and eliminate equipment failure, and make timely adjustments to the self-recording apparatus so that the collected observations scientific, objective and accurate.

A variety of self-recording instruments need to adjust the standard pen-bit
Since the recorded value will be compared with the measured value, if the difference between the two larger, when the barometer error> + -1.5 hPa, thermometer error> + -1.0 ��, hygrometer error> = 10%, should adjust the instrument pen bit. Siphon rain gauge: After the drainage remain in the self-recording paper if 0 line, siphoning from the beginning of recorded 10 mm tip does not refer to place, should adjust the self-recording pen bit (when no precipitation could be used for self-recording paper 8 ~ 10 d, need to raise 1.0 mm per day to raise the pen bit of water so as to avoid overlapping traces a day) [3].

2 Since the difference between recorded and measured values of the main reasons for excessive
(1) dry bulb thermometer readings and the difference is too large. Main reasons: induction part (bimetal) on the integrated dust or water, or dry bulb thermometer numerical misreading; dry bulb dust or water on the plot; thermometer inside scale magnetic plate damage, capillary tube with mercury drops, the black precipitate of oxides, mercury interruption.

(2) and the wet and dry bulb hygrometer reading of difference is too large. On the hygrometer, it may be inclement weather, or from lack of cleaning, hair, dirty (coated with dust), affect the contraction and expansion of fat hair, hair loss (hook ), the weather suddenly changes, and other equipment caused by a difference of lag too. For dry and wet bulb, distilled water may be impure, or contaminated gauze bandage too tight, or too little water or even wet the ball less than 2 / 3 cups of water, but from lack of clean cups, wet and dry bulb may be misreading; improper melting ice in winter, adjust the pen position is not appropriate when the weather conditions, adjust the pen bit of magnification and so on.

(3) groove mercury barometer meter readings and the difference is too large. Barometer may be part of induction with dust; self-recording pen on the pressure-recording paper inappropriate (too large or too small.) Groove terms of mercury table adjust the mercury mercury surface and the tank is not exactly the ivory needle phase (too far or not in place), the adjustment of foot travel is not just with the mercury convex vertex tangent, mercury meter reading is wrong, moving surface trough of mercury within the mercury barometer produce oxides not removed in time, not vertically, hanging barometer.

(4) gauge siphon rain gauge readings and the difference is too large or cause a trace exception. The reasons are: indoor and siphon wall dirty float, resulting in foreign body obstruction; float water, float interior surface of the water rises, the float can not be increased accordingly; siphon and the float chamber side of the tube does not close the connection interface (air leak, drip); siphon curvature inappropriate; float straight rod with the float chamber cover corrosion on the uprights, the two are not parallel, the friction is too large and so on.

Links to Research Papers Download http://www.hi138.com 3 to adjust pen position to note when
(1) numerical difference appears too large, should be carefully analyzed to find the specific cause.

(2) serious repeat, checking and measured values from the record to see if there is the possibility of misunderstanding, and then bad references checker revised correctly.

(3) to change paper every day must be taken to avoid the following phenomena: self-recording paper roll in the minute tube is not tight (loose), both ends of the scale line is not aligned (on the diagonal), bottom of the tube is not close to the clock striking the lower edge (the shift).

(4) adjusting the pen bit of time, preferably immediately after the 20:00 observation adjusted, and timely adjustments recorded in the diary on duty, self-recording paper on the back. If at any other time adjustment, observation records must be measured in order to use interpolation method to calculate the value of the punctuality of the revised range extreme.

(5) adjust the pen position on the selected day of extreme and general station (do not keep the night classes) 02:00 revised records to see if changes need to be jump processing (ie, revised extreme, the difference should be timer readings were calculated before and after the jump.)
(6) to adjust the pen position may be extreme as far as possible to avoid the time, so as not to influence the selection of extreme meteorological records and the continuity and accuracy. Adjustment should be less than the average of the most recent set positive, rather less stressed, not adjustable overdone.

(7) hair hygrometer pen bit of adjustment should be in high humidity conditions (relative humidity> 70%), whether in the low temperature, low humidity or wind speed is very small, should not be adjusted.

4 Summary
A variety of self-recording instrument with the measured value difference is too large, the same self-recording instrument has a lot of daily maintenance [4]. Therefore, we must be cleaned regularly to develop and debug instrument of good habits and avoid all kinds of instruments with the "sick" work . air temperature, humidity, air pressure, rainfall and other meteorological data directly affect the surface accuracy of weather forecasts, weather information and meteorological services, the quality of results. the grassroots member forecasting surface weather stations should consciously abide by the rules and regulations strictly, earnestly maintain peace , on time and inspection equipment, and remove equipment failure, be sure the instrument is in good working condition, reduce or avoid the missing data and the emergence of various unusual records to ensure that records of objective, accurate, complete, for weather forecasting, climate analysis, scientific detailed Research to provide accurate data.

5 References
[1] China Meteorological Administration. Surface weather observing practices [M]. Beijing: China Meteorological Press, 2003.

[2] Chen Huanwu. Ground-based observations of self-recording instruments common fault diagnosis and repair [J]. Journal of Shaanxi Meteorology, 2006 (4): 37.

[3] Sun Yingjie, Zheng Wenqing, Bu Xiang Shuo. Siphon rain gauge and treatment of common faults [J]. Shanxi Meteorology, 2005 (1): 37.

[4] Chiang Wan Chi, Cao long before, Jiao Wen-hong. On the stability and improve the Quality of agricultural gas forecasting [J]. Modern Agricultural Science and Technology, 2009 (19): 276.

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