The product provides the mean temperature or precipitation amount averaged over the available data during the period 1961 through 1990. (For the seasons Nov-Jan and Dec-Feb, the period is Nov 1961-Jan 1991 and Dec 1961-Feb 1991, respectively.) For temperature, the standard deviation for this same range of years is also provided. For precipitation, the median is displayed. The period of record minimum and maximum values and the years of occurrence are listed next. (For seasons crossing a year boundary, the year listed is the starting year.) The station period of record is displayed in the header. Next, the limits for the three categories, "below normal", "near normal" and "above normal" are displayed, along with the last year that fell into each category and what the value was in that year. These are based on a distribution fit to the years 1961 through 1990. The distribution is evaluated such that 33.3% of the years fall into each category. For temperature, the Gaussian distribution is used. For precipitation, a gamma distribution is used.
The routine then allows the user to adjust the distribution to favor a certain category by a given amount. The method employed to accomplish can be found in: Briggs, W.M., and D.S. Wilks, 1995, "Estimating monthly and seasonal distributions of temperature and precipitation using the new CPC long-range forecasts", Journal of Climate, Vol. 9, pp. 818-826. The output provides the adjusted mean and, for temperature, standard deviation. Values at certain points along the adjusted distribution are provided.
| Station: BOSTON LOGAN INT'L ARPT | State: MA | ID: 190770 | ||
| Latitude: 42.36 | Longitude: -71.01 | Elevation: 20 feet | ||
| Station period of record: 1/1/1920-10/12/2000 | ||||
| CLIMOD Product: Seasonal Distributions | Creation Time: 10/13/2000 14:51 EDT | |||
| Element: Average Temperature | Units: degrees F | |||
| Season: December through February | ||||
| Climatological Probabilities | ||
| 1961-1990 Mean | 31.0 | |
|---|---|---|
| Standard deviation | 2.13 | |
| Record minimum | 24.9 in 1933 | |
| Record maximum | 36.7 in 1932 | |
| Category Limits | ||
| Category | Range of values | Year of last occurrence |
| Below normal | <= 30.0 | 1993 ( 27.8 ) |
| Near normal | 30.0 - 31.9 | 1995 ( 30.9 ) |
| Above normal | >= 31.9 | 1999 ( 33.0 ) |
| Adjusted Probabilities - 'Above normal' category increased 10% | |
| Adjusted Mean | 31.4 |
|---|---|
| Standard deviation | 2.08 |
| Percentile | Average Temperature |
| 5 | 28.0 |
| 10 | 28.8 |
| 20 | 29.7 |
| 30 | 30.3 |
| 40 | 30.9 |
| 60 | 31.9 |
| 70 | 32.5 |
| 80 | 33.2 |
| 90 | 34.1 |
| 95 | 34.8 |
For additional assistance, you can e-mail questions to CLIMOD Support (climod_support@nrcc.cornell.edu).