A challenging issue in the hydrologic and meteorologic fields is the spatial, temporal, and seasonal characteristics of precipitation and other meteorological variables (e.g., wind, snow).   MetStat® has a specialized niche to address these challenges using its expansive in-house database of archived climatological and meteorological data, state-of-the-science models/methods and over 20 years of experience to provide high quality datasets and analysis.

Precipitation/rainfall frequency vaWY24hr100yr_smlrlues provide critically important resources for basic hydrologic design, thereby achieving regulatory compliance, public safety, optimization of water infrastructure design and water resource management programs. Precipitation frequency values serve as a fundamental resource that allow the estimation of design rainfall events and ensuing floods in order to optimize planning and design of engineering projects. Precipitation frequency estimates provide engineers and hydrologists the needed information to build safe and efficient hydraulic structures (e.g., culverts, bridges, dam spillways, stormwater/drainage systems). Projects of this nature are of great importance given the costs of lives and property associated with hydrologic structure failures that can be prevented given accurate precipitation frequency statistics. In general, the demand for improved rainfall statistics is driven by governments wishing to develop safe, efficient and cost-effective water retaining structures as well as risk-based analyses.

MetStat® utilizes the regional L-moment frequency analysis approach for computing frequency estimates, which is the state-of-the-science approach that few know how to conduct. MetStat® is uniquely qualified to carry out such projects.

Precipitation frequency estimates (e.g., 100-year 24-hour) are used as basic design criteria for a variety of hydraulic structures such as dams, roadway drainage, bridges and culverts. L-moments and frequency analysis utilize a dataset (annual maximum series or partial duration series) to estimate the characteristics of the underlying population by selecting and parameterizing a probability distribution (e.g., Gumbel, Log-Pearson, Generalized Extreme Value (GEV)).  In addition, MetStat® can assess differences that may exist between precipitation and rainfall-only (i.e., liquid precipitation excluding snow and ice) frequency estimates, especially at higher elevations.

Spatially distributed estimates of meteorological data are becoming increasingly important as inputs to spatially explicit meteorologic, hydrologic, regional, and global models. MetStat® has developed a proven, government-accepted and cost-effective spatial interpolation technique that utilizes a mean monthly/annual/seasonal precipitation to help interpolate between ungauged locations.

A large portion of precipitation frequency analysis and interpolation procedures are allocated to quality control (QC) methods. Potential errors associated with precipitation datasets are gauge under-catch, timing, data shifts, observer error, and metadata (latitude, longitude, elevation). All are essential for an accurate assessment of datasets. MetStat® uses QC processes that examine the timing, magnitude, and interpolated values for the identification of erroneous data.

MetStat® has conducted frequency analyses for the following variables:

  • Precipitation, rainfall
  • Wind speed and gust
  • Snow depth and load
  • 3-, 6- and 12-hour dew point temperature