Climate Data
Information regarding acquisition, processing, and interpretation of climate data that may be related to PhenoCam image data. More information coming soon.
#CLIMOD2 From the CLIMOD website,
The CLimate Information for Management and Operational Decisions (CLIMOD) system provides clients with web access to a vast amount of data and information in the NRCC [Northeast Regional Climate Center] database. Some examples of products available through the CLIMOD system include: daily temperature and precipitation observations, normals and records for several thousand sites around the country and monthly data summaries. Additional derived products, such as growing, heating and cooling degree day accumulations, that are useful for planning and managing climate-sensitive operations, are also available through the CLIMOD system.
CLIMOD2 is a new free to use climate data portal, available online: http://climodtest.nrcc.cornell.edu/. With weather stations positioned across the United States, it should be possible to acquire local climate data relevant to PhenoCam(s) of interest.
When one first visits the site, one is directed to select a data product. For studies comparing climate data to PhenoCam imagery, the product that will be most useful for the majority of users is probably the 'Daily Data Listing.' This product allows one to obtain weather station data for a user-defined range of dates. Details about the Daily Data Listing product can be found here.
After selecting the daily Data Listing product, the 'Options selection' menu will expand. One will here select an output option (HTML table or CSV file), a date range, and which variables one wishes to have reported. A brief explanation of these variables, according to the Daily Data Listing Help, follows:
- Max temp: Maximum recorded temperature
- Min temp: Minimum recorded temperature
- Avg temp: Average temperature
- Obs temp: Temperature at time of observation
- Precipitation: Rain and liquid equivalent of snowfall (melted snowfall)
- Snowfall: Amount of snow that has fallen since last observation
- Snow depth: The combined total depth of both old and new snow on the ground at time of observation
- HDD base 65: Heating Degree Days - A form of degree day used to estimate energy requirements for heating. Heating degree days are calculated as how much colder the mean temperature at a location is than 65 degrees F on a given day.
- CDD base 65: Cooling Degree Days - A form of degree day used to estimate energy requirements for air conditioning or refrigeration. Typically, cooling degree days are calculated as how much warmer the mean temperature at a location is than 65 degrees F on a given day.
- GDD base 50: Growing Degree Days - The number of degrees that the average temperature is above a baseline value. Agricultural related interests use growing degree days to determine planting times and monitor phenological development.
One may choose to have the value, normal, and/or departure from normal reported for each variable. A combination of one or more of these variables may be used in conjunction with PhenoCam imagery to investigate questions that may not be possible with PhenoCam imagery alone.
Variables of particular interest to Phenological studies include average temperature, precipitation, and Growing Degree Days. It should be noted that, although the CLIMOD 2 system only has an option for GDD base 50, other baseline values may be chosen and computed by the user obtaining minimum and maximum temperature data:
GDD base x = ((Max Temp + Min Temp) / 2) - x
It may be desirable to calculate a custom GDD depending on the vegetation type of interest in the PhenoCam's field of view.
Once Options selection is complete, one may search for a weather station from which to obtain records. One may either enter a station ID or search for stations by location. If one wishes to search by location, simply type a state and/or city name into the search box and press enter. A list of stations will be populated in the Station dropdown, and a map showing nearby stations will be displayed. One may either select a station from the dropdown list, or click on a station in the map to activate it.
After a station has been selected, pressing the Go button will return a results page.
It should be noted that entries marked with a 'T' stand for 'Trace amount', which is less than 0.01 inches of precipitation; less than 0.1 inches of snowfall; or less than 1 inch of snow depth. Entries marked 'M' indicate missing data. A fully detailed guide to the meaning of reported results can be found in the General Help and Product info windows, opened by pressing one of the two buttons shown below:
The figure below compares mean camera GCC (smoothed with the per90 method using daily imagery between 10 AM and 2 PM) and mean camera NDVI (also smoothed using the same technique) for the konza PhenoCam site with climate data obtained from the 'MANHATTAN 6 SSW' weather station through CLIMOD 2.
A full resolution version of the above plot can be found here
It should be noted that the NDVI data shown in this plot are not accurate. These NDVI values were calculated from raw values obtained from the IR view of the PhenoCam, without any corrections as suggested by Petach et al. 2014. Moreover, the Konza site suffers from the fact that the RGB and IR views are taken some 10-20 minutes apart, rather than <30 seconds for most sites. Because of this discrepancy, raw IR values for the times that the RGB images were taken are linearly interpolated. These raw interpolated values are then used to calculate the mean NDVI displayed below. A more robust solution is called for, but this will do for now since this is just for demonstration purposes...
#High Plains Regional Climate Center - Web Data Access
The High Plains Regional Climate Center maintains data on a large number of automated weather stations in Colorado, Iowa, Kansas, Minnesota, Missouri, Montana, North Dakota, Nebraska, South Dakota, and Wyoming.
Such data may be useful for comparison to PhenoCams located within the HPRCC network. New users will have to request an account via email, which can then be used to access the Web Data Access portal.
It should be noted that official help documentation on the use of the HPRCC Web Data Access Portal is available on the web site, once one has logged in. Clicking on the 'HELP' link (the last option in the upper left hand list of options) will take you to the help specific to whichever page you are currently on (e.g., clicking 'HELP' while on the 'Select a Station' page will pull up help about that page).
One should first select a weather station from which to acquire data. Click on the 'Select a Station' link at the top left of the page. A station search and selection page should load, which will allow one to add stations to a list that will be used to search for data later.
To search for stations, identify a state and network. In this case, the Automated Data Network may be sufficient, although users may wish to use one or more networks (e.g., the Automated Weather Data Network and the National Weather Service & Cooperative Observer Network)
If one has no prior knowledge of where Automated Network Stations are located near PhenoCam(s) of interest, static maps showing the location of stations can be found here. An example of one such map for Nebraska is shown below:
Those searching for National weather Service stations can use the web search interface available here, which will allow one to interactively search for NWS stations via a web-map interface.
To add a station to the list, click on the station name and then click Click Here to Add The Highlighted Station(s) to the Current List.
Most users hoping to compare climate data to PhenoCam imagery will find the 'Raw Data Report' to be of most use. Clicking on the 'Raw Data Report' link will direct the user to a 'Data Retrieval' page. Here, one will first choose a station from the Current Station List.
Next, a 'Time frame' must be selected. One may either choose 'Begin and End Date', 'Last N Days', or 'Year to Date'. Most users will find the 'Begin to End Date' of most use, as this will allow one to search for data between the dates of PhenoCam operation that one is interested in. Finally, one must select an output Format, the type of units one wishes variables to be reported in, and the sample interval. Once these values are selected, press Click Here to Select these Options.
The page will refresh, presenting new options for selecting the values of the Time frame specified above. If one selected 'Begin to End Date', for example, one would now enter the starting and ending date. When this has been filled out, click Click Here to Submit Data Request.
When the system has fulfilled one's request, the output will be displayed in the format requested by the user. An example of the 'CSV with text header' format is shown below:
