农业和气象网络
NDAWN sites span the state and provide data critical to theapplication of pesticides.
North Dakota agriculture ranks high in the nation's cropproduction: No. 1 in durum and spring wheat, barley, sunflower,flax, and all edible beans, No. 2 in oats and all wheat ,No. 3 inpotatoes, and No. 4 in rye and sugar beets. To maintain theserankings, our agriculture must continue to produce high quantitiesof quality crops despite unpredictable attacks from diseases,insects, and other antagonistic factors.
Pesticide application, although environmentally controversial ,is the farmer's main tool to control crop diseases and insects.Scientists have identified the critical weather conditions thatcontrol development of some organisms, and have written programsthat mimic or model this relationship. By using current weatherdata as input, a computer model can accurately track a specificdisease or an organism's stage of development. Based on thisinformation, a farmer knows if and when to spray pesticides,minimizing the potential health and litigation issues arising fromspray drift, which are always of concern with pesticideapplication.
In 1989, weather monitoring systems were installed under thesupervision of John W. Enz, NDSU Agricultural Climatologist, at sixagriculture experimental stations across North Dakota. To daythe system has grown to 50weather stations, and is known as theNorth Dakota Agricultural Weather Network (NDAWN). It is anenvironmentally sound electronic weather monitoring system, and isman-aged by John Enz, Professor, Radu Carcoana and Greg Brockberg,Research Specialists from NDSU, Soil Science, ClimatologySection. The data collected by this system are used by anincreasing number of individuals and institutions for an amazinglywide variety of purposes.
农业和气象网络
NDAWN sites, like the one pictured to the right, are foundthrough out the state and provide basic and custom measurements fora variety of individuals and institutions.
Our standard weather stations measure air temperature andrelative humidity with a Vaisala HMP35C sensor, wind speed anddirection with Met One 014A and024A sensors, solar radiation withLI-COR LI200S and LI200X pyranometers, rainfall with a TexasElectronicTE525 tipping bucket rain gauge, barometric pressure witha Vaisala PTA427sensor,and soil temperature at 10-cmdepths underbare and turf cover conditions with thermocouples or thermistors.Data are recorded and summarized hourly and daily by 41 CR10dataloggers and nine 21Xs. All sites are accessed byphone:37with DC112 phone modems (seven with cellular phones),and 11 withVS1voice modems. Two stations are accessed via radio telemetry.
Voice modems provide instantaneous weather data (wind speed anddirection, temperature, relative humidity, and the amount ofprecipitation since midnight).The data helps farmers decide if theappropriate legal weather conditions are met for ground or aerialpesticide spraying.
Seasonal sensors are installed at sever-al stations to monitorspecific parameters. Temperature and RH under a mature sugar beetcanopy (one foot from the ground) is measured with anadditionalHMP35C. Several extra thermistors are used tomeasure the temperature of the sugar beet root and crown at harvesttime. Solar radiation is an important parameter incalculating the crop potential evapo transpiration (PET). PETis used to calculate the daily and weekly crop water use, whichhelps farmers decide when and how much to irrigate.
Beyond the basic measurements, special research projects requirecertain stations monitor other variables via Campbell's AM416multiplexer. At two sites, temperatures are monitored at 14depths (10 feet max)under highway pavement in a joint researchproject with the ND Department of Transportation. Groundwater level is monitored in water wells, as part of a long termNDSU research program in the Sheyenne National Grasslands. Soil temperatures are measured once per hour at12 depths (6 feetmax) at 13 stations around the state as part of an ongoing researchproject. At another site soil temperatures are profiled inlocations on both north- and south-facing slopes.
To provide accurate, reliable data(because bad data is worsethan no data)we have concentrated our efforts to finance anddevelop an exigent program of quality control (QC) and preventivemaintenance (PM). QC is upheld by two daily data qualitycontrol filters. One Is performed by the High Plains ClimateCenter in Lincoln, Nebraska, which also retrieves daily data. The second is per-formed by the research specialists fromNDSU. PM minimizes station downtime and expense, but requiresa good supply of factory-calibrated spare parts, ranging from extraclamps and sensors to CR10sand 21Xs.
Each station is visited annually for a standard check-up. Wealso maintain a detailed log of all actions and events thatoccurred at each station. In addition to the standard checkupsthere are emergency situations (besides lightning strikes, birddroppings on pyranometers or in the rain gauge funnel, or snow onsolar panel) that require additional travel.
The cooperation with applications engineers at CampbellScientific and their availability by phone is invaluable inpin-pointing problems. Their contribution in solving manyspecific and unusual situations is critical. On one occasion,a problem with a phone line was found in a cooperative effort on afour-way phone conference. Paul, an Environmental Specialistwith the ND National Guard(the station’s owner) was in the car,John was in the office monitoring the station by computer, Radu wasat the station along with Harris from the phone company, and Bart,the CSI applications engineer, was in Logan, Utah.
农业和气象网络