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Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using drainage and runoff water recycling through subirrigation. Limited information regarding subirrigation timing and intensity hinder its promotion across the region. Seven water table management strategies were simulated using DRAINMOD calibrated for three locations with different soil series in northwest Ohio, under 1984 to 2013 climate conditions, and were compared based on annual relative yield, subirrigation water volume, relative water discharge, and management intensity. Annual relative yields ranged between 63.1% and 64.4% at the Defiance site and were not significantly different between the water table management strategies. Under subirrigation, relative yields ranged from 87.3% to 93.2% and 80.4% to 90.8%, respectively, at the Fulton and Van Wert sites and were significantly larger than under free subsurface drainage. Annual subirrigation water volumes were significantly lower under continuous subirrigation from V3 stage at all three locations. Subirrigation water volumes at the Fulton and Van Wert sites were particularly lower with continuous subirrigation starting at V9. Relative water discharges were similar across all water table management strategies at the Defiance site and larger under free subsurface drainage at the Fulton and Van Wert sites. Free subsurface drainage was the most appropriate option for the Defiance site in terms of water table management because subirrigation did not improve the relative yield but consumed water (and, consequently, energy for pumping). For the Fulton and Van Wert sites, continuously subirrigating from V9, with the control weir set at 61 cm below ground surface and raised to 35 cm below ground surface at tasseling improved the relative yield while using less subirrigation water volumes and generating no greater relative water discharge (hence no greater dissolved nutrient loads) than the other subirrigation options. This strategy potentially reduces labor costs at locations where subirrigation is appropriate, enhancing the economic viability of subirrigation, and is the most applicable strategy to other major maize-growing areas in the Midwest. Results indicate water table management and subirrigation will benefit Midwestern maize production under projected climates, which suggests increased potential for water stress in most growing seasons by 2041 to 2070. Future studies, extending this approach to more diverse regions, accompanied by more in-depth economic assessments, are needed to further evaluate potential benefits of subirrigation.

Subirrigation is employed to supply water to crop root zones via subsurface drainage systems, which are typically installed for the purpose of excess soil water removal. Crop yield increases due to subirrigation have been demonstrated in numerous studies, but there is limited information regarding yield under future climate conditions when growing season conditions are expected to be drier in the U.S. Corn Belt. DRAINMOD was calibrated and validated for three locations with different soil series in northwest Ohio and used to investigate maize relative yield differences between subirrigation and free subsurface drainage for historic (1984–2013) and future (2041–2070) climate conditions. For historic conditions, the mean maize relative yield increased by 27% with subirrigation on the Nappanee loam soil, but had minimal effect on the Paulding clay and Hoytville silty clay soils. Maize relative yield under free subsurface drainage is predicted to decrease in the future, causing the relative yield difference between free subsurface drainage and subirrigation practices to nearly double from 9% to 16% between the historic and future periods. Consequently, the subirrigation practice can potentially mitigate adverse future climate change impacts on maize yield in northwest Ohio.

Climate change projections for the Midwest U.S. indicate a future with increased growing season dryness that will adversely impact crop production sustainability. Systems that capture water for later subirrigation use have potential as a climate adaptation strategy to mitigate this increased crop water stress. Three such systems were operated in northwest Ohio from 1996 to 2008, and they exhibited substantial crop yield benefits, especially in dry growing seasons, but also to a lesser extent in near normal or wet growing seasons. The goal of this research was to estimate the increase in crop yield benefits of water capture and subirrigation systems that can be expected under projcted 2041–2070 climate conditions in northwest Ohio. Historical subirrigated field crop yield differences with fields having free drainage only, relative to growing season dryness/wetness, were used to determine future northwest Ohio subirrigated field crop yield increases, based on the modeled climate for 2041–2070. Climate records for 2041–2070 were projected using three bias corrected model combinations, CRCM+CGCM3, RCM3+GFDL, and MM5I+HadCM3. Growing season dryness/wetness was classified based on the difference between rainfall and the crop adjusted potential evapotranspiration using the 1984–2013 climate record at the three system locations. Projected 2041–2070 growing season precipitation varied substantially between the three model combinations; however, all three indicated increased growing season dryness due to rising temperature and solar radiation. The overall subirrigated field corn yield increase rose to an estimated 27.5%–30.0% in 2041–2070 from 20.5% in 1996–2008, while the subirrigated field soybean yield increase improved from 12.2% in 1996–2008 to 19.8%–21.5% for 2041–2070. Consequently, as growing season drought becomes more frequent, the crop yield benefits with water capture and subirrigation systems will improve, and these systems therefore provide a viable climate adaptation strategy for agricultural production.

Nebraska is situated at the intersection of the northern and southern Great Plains, exhibiting a dramatic longitudinal gradient for precipitation and humidity, and benefiting from groundwater resources. The continental climate is highly variable temporally both for temperature and precipitation. Our assessment of long-term meteorological observations shows that over the last century the annual average temperature in Nebraska has warmed approximately 0.6°C, which is similar to the increase in the global average temperature over the same time period. Furthermore, we found minimum temperatures have warmed more than maximum temperatures, and winter and spring show the strongest warming. We found no significant long-term trend in annual precipitation, but seasonal variations exist, namely with wetter springs and falls, and drier winters and summers. The number of days having temperature extremes (both hot and cold) has decreased over time. We found an overall increase in growing season length.

Climatic records of wind speed are analyzed for eight long-term monitoring locations in the Beaufort/Chukchi coastal region of the Arctic, over the period from 1979 to 2009. Data for this study originated from three national observing networks throughout the Beaufort/Chukchi region and were uniformly quality controlled using a combination of automated and manual checks. The climatology of wind speed was developed over the study period and includes analyses of mean wind speed, extremes, and frequency distributions. Trends in monthly and annual wind speed were examined. The climatology illustrates strong distinctions between coastal and interior locations, strong seasonal characteristics, and diurnal cycles in wind speed. Negative trends in wind speed were apparent at several locations, particularly at locations in Alaska. Many of these trends were statistically significant (95% CI). To assess the impact of artificial changes on trends, station data were homogenized with respect to metadata records. Trends were recalculated and the effects were discussed. Possible drivers of wind speed trends were also discussed, including multi-decadal climate signals. Results from the climatology and trend analyses were compared with output from the North American Regional Reanalysis (NARR). Negative biases in wind speed were apparent at most locations throughout the year in NARR. Trends in NARR wind speed opposed in situ trends, at most locations. Improved knowledge of wind speed records and reanalysis output is important in this rapidly changing region.

Subirrigation has been proposed as a water table management practice to maintain appropriate soil water content during periods of high crop water demand on subsurface drained croplands in the Corn Belt. Subirrigation takes advantage of the subsurface drainage systems already installed on drained agricultural lands to remove excess soil water after precipitation events. However, limited information regarding corn yield under subirrigation is available to promote its implementation at a large scale. In addition, its performance within the backdrop of climate change has not been explored in the context of the Corn Belt. DRAINMOD was calibrated and validated for a location with Nappanee loam soil in the Maumee River Basin in Northwest Ohio. The model was then used to investigate relative corn yield differences between subirrigation and free subsurface drainage for historical (1984-2013) and projected future (2041-2070) climate conditions. For historical conditions, the mean relative corn yield increased by 26.5% under subirrigation. Under free subsurface drainage, corn relative yields were lower for future climate conditions than for historical climate conditions. For the projected future climate conditions, overall relative corn yields under subirrigation increased by 36.5% compared to relative yields under free subsurface drainage. Subirrigation contributed in sustaining relative corn yields under future climate conditions.

Agriculture in the Great Lakes region has benefited from precipitation patterns that are fairly regular throughout the year. The beneficial climate, coupled with soils that generally have high water holding abilities, has allowed agriculture in the region to become highly productive and a substantial contributor to the region’s economy. However, predicted shifts in temperature and precipitation patterns towards warmer and wetter winter and spring months, a greater frequency of intense storms throughout the year, and more severe and longer droughts in the summer suggest the potential for decreased crop yields in the future unless ways are found to provide additional water to crops during growing season drought, while also being able to quickly remove excess soil water when conditions are wet.

Meteorological observations from more than 250 stations in the Beaufort and Chukchi Sea coastal, interior, and offshore regions were gathered and quality-controlled for the period 1979 through 2009. These stations represent many different observing networks that operate in the region for the purposes of aviation, fire weather, coastal weather, climate, surface radiation, and hydrology and report data hourly or sub-hourly. A unified data quality control (QC) has been applied to these multi-resource data, incorporating three main QC procedures: the threshold test (identifying instances of an observation falling outside of a normal range); the step change test (identifying consecutive values that are excessively different); and the persistence test (flagging instances of excessively high or low variability in the observations). Methods previously developed for daily data QC do not work well for hourly data because they flag too many data entries. Improvements were developed to obtain the proper limits for hourly data QC. These QC procedures are able to identify the suspect data while producing far fewer Type I errors (the erroneous flagging of valid data). The fraction of flagged data for the entire database illustrates that the persistence test was failed the most often (1.34%), followed by the threshold (0.99%) and step change tests (0.02%). Comparisons based on neighboring stations were not performed for the database; however, correlations between nearby stations show promise, indicating that this type of check may be a viable option in such cases. This integrated high temporal resolution dataset will be invaluable for weather and climate analysis, as well as regional modeling applications, in an area that is undergoing significant climatic change.