The above unpublished report is included in the downloadable file for this layer as a PDF file named "IndianaWindMappingReport.pdf."
This raster layer is one of a set of six showing mean wind speeds and mean wind power at various heights above the ground. The six layers are named "WINDSPD30_IN," "WINDSPD50_IN," "WINDSPD70_IN," "WINDSPD100_IN," "WINDPWR50_IN," and "WINDPWR100_IN."
"Using the MesoMap system, TrueWind has produced maps of mean wind speed in Indiana for heights of 30, 50, 70, and 100 m above ground, as well as a map of wind power at 50 m. TrueWind has also produced data files of the predicted wind speed frequency distribution and speed and energy by direction. The maps and data files are provided on a CD with the ArcReader software, which will enable users to view, print, copy, and query the maps and wind rose data.
"The MesoMap system consists of an integrated set of atmospheric simulation models, databases, and computers and storage systems. At the core of MesoMap is MASS (Mesoscale Atmospheric Simulation System), a numerical weather model, which simulates the physics of the atmosphere. MASS is coupled to a simpler wind flow model, WindMap, which is used to refine the spatial resolution of MASS and account for localized effects of terrain and surface roughness. MASS simulates weather conditions over a region for 366 historical days randomly selected from a 15-year period. When the runs are finished, the results are input into WindMap. In this project, the MASS model was run on a grid spacing of 1.7 km and WindMap on a grid spacing of 200 m.
"The wind maps show that the best wind resource in Indiana is found in the northcentral part of the state. The mean wind speed at 50 m height between Indianapolis, Kokomo, and Lafayette, and to the northwest of Lafayette, is predicted to be in the range of 6.5 to 7 m/s, and the mean wind power is predicted to be about 250 to 350 W/m2, or NREL class 2 to 3. In the rest of northern Indiana, the wind speed tends to be around 0.5 m/s lower, and the wind power is a solid class 2. In southern Indiana, a wind speed of 4.5 to 6 m/s and a wind power class of 1 to 2 prevails. The main reason for this wind resource distribution pattern is that the land is much more forested in the southern half of the state than in the northern half. Topography also plays a role, as does the track of the jet stream."
"The Indiana Department of Commerce is interested in assessing the wind resource of Indiana and finding suitable sites for wind energy projects. Conventional field techniques of wind resource assessment can be time consuming, however, and often depend heavily on local meteorological expertise as well as the availability of reliable and representative wind measurements. Conventional wind flow models, on the other hand, have often proven inaccurate in complex wind regimes, and even in moderate terrain their accuracy can decline substantially with distance from the nearest available reference mast.
"Mesoscale-microscale modeling techniques offer a solution to these challenges. By combining a sophisticated numerical weather model capable of simulating large-scale wind patterns with a microscale wind flow model responsive to local terrain and surface conditions, they enable the mapping of wind resources over large regions with much greater accuracy than has been possible in the past. In addition, they do not require surface wind data to make reasonably accurate predictions. While on-site measurements are still required to confirm the predicted wind resource at any particular location, mesoscale-microscale modeling can greatly reduce the time and cost to identify and evaluate potential wind project sites.
"The objective of the current project was to use MesoMap to create high-resolution wind resource maps of Indiana and to provide wind resource data in a format enabling the Indiana Department of Commerce to assess potential sites in a GIS. These objectives have been met. In the following sections, we describe the MesoMap system and mapping process in detail; how MesoMap was applied in this project; the validation process and results; the final wind maps and data files; and guidelines for the use of the maps."
"The MesoMap system has three main components: models, databases, and computer systems.
"At the core of the MesoMap system is MASS (Mesoscale Atmospheric Simulation System), a numerical weather model that has been developed over the past 20 years by TrueWind partner MESO, Inc., both as a research tool and to provide commercial weather forecasting services. MASS simulates the fundamental physics of the atmosphere including conservation of mass, momentum, and energy, as well as the moisture phases, and it contains a turbulent kinetic energy module that accounts for the effects of viscosity and thermal stability on wind shear. As a dynamical model, MASS simulates the evolution of atmospheric conditions in time steps as short as a few seconds. This creates great computational demands, especially when running at high resolution. Hence MASS is usually coupled to a simpler but much faster program, WindMap, a mass-conserving wind flow model. Depending on the size and complexity of the region and requirements of the client, WindMap is used to improve the spatial resolution of the MASS simulations to account for the local effects of terrain and surface roughness variations.
"The MASS model uses a variety of online, global, geophysical and meteorological databases. The main meteorological inputs are reanalysis data, rawinsonde data, and land surface measurements. The reanalysis database – the most important – is a gridded historical weather data set produced by the US National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR). The data provide a snapshot of atmospheric conditions around the word at all levels of the atmosphere in intervals of six hours. Along with the rawinsonde and surface data, the reanalysis data establish the initial conditions as well as updated lateral boundary conditions for the MASS runs. The MASS model itself determines the evolution of atmospheric conditions within the region based on the interactions among different elements in the atmosphere and between the atmosphere and the surface. Because the reanalysis data are on a relatively coarse, 200 km grid, MASS is run in several nested grids of successfuly finer mesh size, each taking as input the output of the previous nest, until the desired grid scale is reached. This is to avoid generating noise at the boundaries that can result from large jumps in grid cell size. The outermost grid typically extends several thousand kilometers.
"The main geophysical inputs are elevation, land cover, vegetation greenness (normalized differential vegetation index, or NDVI), soil moisture, and sea-surface temperatures. The global elevation data normally used by MesoMap were produced by the US Geological Survey in a gridded digital elevation model, or DEM, format from a variety of data sources.1 The US Geological Survey, the University of Nebraska, and the European Commission’s Joint Research Centre (JRC) produced the global land cover data in a cooperative project. The land cover classifications are derived from the interpretation of Advanced Very High Resolution Radiometer (AVHRR) data – the same data used to calculate the NDVI. The model translates both land cover and NDVI data into physical parameters such as surface roughness, albedo, and emissivity. The nominal spatial resolution of all of these data sets is 1 km. Thus, the standard output of the MesoMap system is a 1 km gridded wind map. However, much higher resolution maps can be produced where the necessary topographical and land cover data are available. In the United States, the resolution is typically 100 to 400 m.
"The MesoMap system creates a wind resource map in several steps. First, the MASS model simulates weather conditions over 366 days selected from a 15-year period. The days are chosen through a stratified random sampling scheme so that each month and season is represented equally in the sample; only the year is randomized. Each simulation generates wind and other weather variables (including temperature, pressure, moisture, turbulent kinetic energy, and heat flux) in three dimensions throughout the model domain, and the information is stored at hourly intervals. When the runs are finished, the results are compiled into summary data files, which are then input into the WindMap program for the final mapping stage. The two main products are usually (1) color-coded maps of mean wind speed and power density at various heights above ground and (2) data files containing wind speed and direction frequency distribution parameters. The maps and data can then be compared with land and ocean surface wind measurement, and if significant discrepancies are observed, adjustments to the wind maps can be made."
It is required that the Indiana Geological Survey be cited in any products generated from this data. The following source citation must be included: WINDPWR50_IN: Mean Wind Power at Height of 50 Meters above Ground, Derived from Mesoscale Atmospheric Simulation System and WindMap (TrueWind Solutions, 200-Meter Grid).
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.
"In collaboration with the National Renewable Energy Laboratory, TrueWind subsequently validated the wind maps using data from 22 stations. The data were first extrapolated to a height of 50 m. The predicted wind speeds are on average about 0.3 m/s higher than the observed/extrapolated speeds. The root-mean-square discrepancy is 0.6 m/s, or about 10% of the average of all the stations. After accounting for uncertainty in the data, we estimated the map error margin (one sigma) to be 0.5 m/s, or 8.5%. The error margin in meters/second is comparable to that obtained in other MesoMap projects, but in percentage terms it is somewhat larger than usual. This is mainly because of the moderate average speed (5.9 m/s at 50 m) of the Indiana stations. In addition, the validation sample includes data from five stations which have rather low mean speeds compared to other stations in their vicinity. If these stations are excluded, the mean bias becomes 0.1 m/s, and the rms discrepancy becomes 0.4 m/s, or 6%, which is comparable to the error margin of the data.
"While the validation confirmed the overall accuracy of the maps, it also revealed some areas where MesoMap appears to have either underestimated or overestimated the wind resource to a moderate degree. With the agreement of NREL, we adjusted the predicted wind speed and power in parts of central and southwestern Indiana."
See the file "IndianaWindMappingReport.pdf" for additional information.
It is required that the Indiana Geological Survey be cited in any products generated from this data. The following source citation must be included: WINDPWR50_IN: Mean Wind Power at Height of 50 Meters above Ground, Derived from Mesoscale Atmospheric Simulation System and WindMap (TrueWind Solutions, 200-Meter Grid).
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.