Summer Wind Speed Research Articles

Links between atmospheric aerosols and sea state in the Arctic Ocean

Sea spray emission is the largest mass flux of aerosols to the atmosphere with important impact on atmospheric radiative transfer. However, large uncertainties still exit in constraining this mass flux and its climate forcing, in particular in the Arctic, where sea ice and relatively low wind speed in summer constitute a significantly different regime compared to the global ocean. Sea state conditions and marine boundary layer stability are also critical variables, but their contribution is often overlooked. Here we present concurrent observations of sea state using a novel stereo camera system, of sea spray through coarse mode aerosols, and of meteorological variables to determine boundary layer stability in the Barents and Kara Seas during the 2021 Arctic Century Expedition. Our findings reveal that aerosol concentrations were highest over open waters, closely correlating with wave height, followed by wind speed, wave steepness, and wave age. Notably, these correlations were stronger under unstable marine boundary layer conditions, reflecting immediate sea spray generation. By analysing various combinations of sea and atmospheric variables, we identified the wave height Reynolds number as the most effective indicator of atmospheric sea spray concentration, explaining 57% of its variability in unstable conditions. Our study underscores the need to consider sea state, wind, and boundary layer conditions together to accurately estimate atmospheric sea spray concentrations in the Arctic.

A Method for Identifying the Dominant Meteorological Factors of Atmospheric Evaporative Demand in Mid‐Long Term

AbstractTo better understand the changes in the atmospheric evaporative demand (AED) in the context of global warming, the anomaly contribution analysis is presented to estimate mid‐long term contributions of meteorological factors to the AED. The Pearson correlation coefficient (RP) between the total contribution (ψ) of meteorological factors and the relative variation (ϕ) of the AED, and the Sen's trend slope (βS) of (ϕ, ψ) scatters are used to evaluate the applicability of the method. The smaller the values of |1 − RP| and |1 − βS|, the more applicable the method is. To validate the method, the reference crop evapotranspiration is employed as a proxy for the AED. The multi‐year contribution analysis is used as a comparison approach, which can only investigate the dominant meteorological factors of the AED in long term. Moreover, the Huaihe River basin of China is taken as a case study. Results show that (a) the values of |1 − RP| and |1 − βS| in mid‐long term are less than 0.1 in most cases when applying the anomaly contribution analysis, and the mid‐long term contribution processes of meteorological factors to the AED are clearly demonstrated; and (b) the wind speed and sunshine hours are the two most dominant factors (the total absolute contribution exceeds 60%) in long term, but they are not always the dominant factors in mid‐long term (e.g., wind speed in summer, and sunshine hours in winter). Therefore, the anomaly contribution analysis is a reasonable and effective method, which can help to gain insights into the changes in the AED.

Effect of urbanization on gust wind speed in summer over an urban area in Eastern China

Previous studies have extensively examined effects of urbanization on mean wind speed, but few studies were aimed at gust wind speed, while large wind gust could cause safety and economic hazard to a variety of activities. In this study, the effect of urbanization on the gust wind speed in Nanjing, China is assessed using the Weather Research and Forecasting (WRF) model with a parameterization of the gust wind speed. The WRF simulations are run for the summer period of 2013 with the underlying surface before and after the urbanization. The results indicate that although the mean wind speed is reduced, the gust wind speed in the urban areas is increased significantly due to the enhanced friction velocity and less atmospheric stability induced by the urbanization, while the contribution of deep convection is relatively small. The gust wind speed increases more in the nighttime (0.6–0.9 m s−1) than in the daytime (less than 0.3 m s−1), since the turbulence is enhanced more in the nighttime than in the daytime after the urbanization. The probability distribution shows that the increase of gust wind speed is mainly between 0.0–0.5 m s−1 in the urban areas. In different urban land categories, the increase of the gust wind speed is larger in the commercial or industrial areas than in high-intensity and low-intensity residential urban areas. Averagely, the gust wind speed in the entire city after the urbanization increases by 0.02, 0.36 and 0.19 m s−1 for the daytime, nighttime and daily mean, respectively.

Characterizing wind fields at multiple temporal scales: A case study of the adjacent sea area of Guangdong–Hong Kong–Macao Greater Bay Area

Temporal characteristics and evolutionary patterns of offshore wind fields directly affect the stability and safety of coastal engineering and structures. In this research, ECMWF-ERA5 reanalysis wind field data were used to analyze the wind field characteristics in the adjacent sea area of Guangdong–Hong Kong–Macao Greater Bay Area (GBA) at multiple temporal scales. It can provide scientific basis for marine equipment construction and coastal engineering management in the GBA. Statistical analysis was performed to investigate characteristics of winds at multiple temporal scale, in combination with Mann–Kendall (MK) and Pettitt test methods to judge the abrupt change characteristics of the wind field climate state over a long period. Results show that during the past 42 years, in the adjacent sea area of GBA, the usual wind direction is northeast throughout the year. The wind speed has a slow downward trend year by year. However, there is no abrupt change. The maximum wind speed in winter is controlled by the northeast monsoon, and the minimum wind speed in summer is related to the activity of subtropical high pressure. Moreover, in terms of transition time, the wind transition from summer to winter is shorter than that from winter to summer.

Analysis and Prediction of Wind Speed Effects in East Asia and the Western Pacific Based on Multi-Source Data

With the increasing problem of global warming caused by the massive use of fossil fuels, biomass energy as a renewable energy source has attracted widespread attention throughout the globe. In this paper, we analyzed the spatial and temporal variation in wind energy in the East Asia and Western Pacific areas using IGRA site data, ERA5, and NCEP/NCAR reanalysis data from 2000 to 2021, and multi-variate empirical orthogonal function (MV-EOF) decomposition with the Pettitt mutation test, and the seasonal autoregression integrated moving average (SARIMA) model was used to predict the trend of wind speed. The spatial and temporal variations in wind energy in East Asia and Western Pacific areas were analyzed, and it was found that the richer wind-energy resources were mainly concentrated in the “Three Norths” (North China, Northwest China, and Northeast China) and Mongolia, followed by the Western Pacific areas. In addition, the T’ai-hang Mountains and the Qinghai-Tibet Plateau in China block the wind resources in the eastern and southern regions of East Asia, resulting in a shortage of wind resources in this region. In addition, the summer wind speed is significantly lower than in the other three seasons. The first-mode contributions of the MV-EOF wind field and geopotential heights, respectively, are 29.47% and 37.75%. The results show that: (1) There are significant seasonal differences in wind-energy resources in the study area, with the lowest wind speed in summer and the highest wind speed in winter. (2) The wind energy in the study area has significant regional characteristics. For example, China’s Qinghai-Tibet Plateau, Inner Mongolia, Xinjiang region, and Mongolia are rich in wind-energy resources. (3) Wind-energy resources in the study area have gradually increased since 2010, mainly due to changes in large-scale oceanic and atmospheric circulation patterns caused by global warming.

Wind simulation using different parameters in a weather research and forecasting model

A study designed different parameter schemes for a weather research and forecasting model to simulate hourly winter and summer wind speed and direction at a wind-farm tower in China. The schemes were found to reproduce the local wind conditions accurately and simulate wind direction very well. The results showed that one scheme performed better for the wind speed and wind direction simulation at 10 and 90 m height in the winter, while another performed better for simulation at 10 m height in the summer. The results for these schemes showed that the correlation coefficients of wind speed and wind direction were 0.75 and 0.62 in winter and 0.55 and 0.44 in summer, respectively. Overall, the parameterised model exhibited better simulation of the wind speed than wind direction, and was better in winter than in summer.

Incorporating Industrial and Climatic Covariates into Analyses of Fish Health Indicators Measured in a Stream in Canada’s Oil Sands Region

Industrial and other human activities in Canada’s oil sands region (OSR) influence the environment. However, these impacts can be challenging to separate from natural stresses in flowing waters by comparing upstream reference sites to downstream exposure locations. For example, health indicators of lake chub (Couesius plumbeus) compared between locations in the Ells River (Upper and Lower) in 2013 to 2015 and 2018 demonstrated statistical differences. To further examine the potential sources of variation in fish, we also analyzed data at sites over time. When fish captured in 2018 were compared to pooled reference years (2013–2015), results indicated multiple differences in fish, but most of the differences disappeared when environmental covariates were included in the Elastic Net (EN) regularized regression models. However, when industrial covariates were included separately in the EN, the large differences in 2018 also disappeared, also suggesting the potential influence of these covariables on the health of fish. Further ENs incorporating both environmental and industrial covariates along with other variables which may describe industrial and natural influences, such as spring or summer precipitation and summer wind speeds and distance-based penalty factors, also support some of the suspected and potential mechanisms of impact. Further exploratory analyses simulating changes from zero and the mean (industrial) activity levels using the regression equations respectively suggest effects exceeding established critical effect sizes (CES) for fish measurements may already be present or effects may occur with small future changes in some industrial activities. Additional simulations also suggest that changing regional hydrological and thermal regimes in the future may also cause changes in fish measurements exceeding the CESs. The results of this study suggest the wide applicability of the approach for monitoring the health of fish in the OSR and beyond. The results also suggest follow-up work required to further evaluate the veracity of the suggested relationships identified in this analysis.

Dynamical downscaling of inland and offshore near‐surface wind speed over China inCORDEXEast Asia Phase I andIIexperiments

AbstractWithin the frameworks of the Coordinated Regional Downscaling Experiment‐East Asia first and second phase (CORDEX‐EA‐I and CORDEX‐EA‐II), the impact of spatial resolution, physical parameterization schemes and spectral nudging (SN) on simulating inland and offshore near‐surface wind speed over China is evaluated. By using WRF and RegCM4 models, the CORDEX‐EA simulations driven by the ERA‐Interim reanalysis data are conducted from 1989 to 2008. The regional climate models (RCMs) have the capacity to simulate the spatial patterns of surface wind, although significant overestimations exist over inland China. The WRF CORDEX‐EA‐II experiments with increasing horizontal resolution perform better in reproducing both inland and offshore wind speed than the CORDEX‐EA‐I experiments. Moreover, the experiments with SN can significantly reduce the positive biases of surface wind speed. For the temporal variation of wind speed, almost all the simulations show larger biases in winter than in summer. Particularly, the simulated wind speed in summer in the RegCM4 experiment with CLM3 land surface model (RCC‐II) is close to the observations. The extreme wind speed can be well reproduced by WRF simulations, and the SN experiments perform better than the experiments without SN (NOSN). In addition, the overestimations of surface wind speed can be partly explained by the overestimations of the wind field at 850 hPa level inherited from ERA‐Interim reanalysis and the increase of temperature gradient between the land and ocean in winter.

Multiple Linear Regression Model of Environmental Variables, Predictors of Global Solar Radiation in the Area of East Lima, Peru

Multiple regression models are very relevant to predict values using predictor variables. The objective of this study was to predict the global solar radiation in the year 2019 in the area of East Lima, Peru. Three continuous quantitative predictor variables were analyzed: temperature, humidity, wind speed and the response variable was global solar radiation, resulting in a model with excellent significance p<0.001 that shows the prediction is effective. The multiple linear regression method was used, finding an average global radiation of 175 W/m2 and predictor variables with average temperature of 19.2 °C, humidity 23.9% and wind speed 1.77 m/s, with the highest temperature in summer recorded at 24.6°C, the highest humidity of 51.2% in autumn, the highest wind speed in summer at 2.63 m/s and the highest maximum global solar radiation in spring with 183 W/m2.

Variations in outdoor thermal comfort in an urban park in the hot-summer and cold-winter region of China

• Outdoor thermal comfort is evaluated in an urban park in a hot-summer and cold-winter region of China (Chengdu). • Machine learning techniques are applied to determine the (nonlinear) relationship between thermal sensation vote and meteorological factors. • The effect of landscape spaces on human thermal comfort varies across the season. • NTR of PET is 6.79 °C to 19.90 °C, and NTR of UTCI is 13.27 °C to 27.25 °C. TAR of PET is 2.8 °C to 21.9 °C, and TAR of UTCI is 8.1 °C to 28.3 °C. Global warming and rapid urbanization have exacerbated the urban heat island effect. Urban parks contribute to alleviating such an effect and achieving the “carbon emission peak before 2030” and “carbon neutrality before 2060” goals of China. Their popularity is considerably influenced by human thermal comfort. However, limited thermal comfort studies have been conducted in the hot-summer and cold-winter region of China. This study examines human thermal comfort in different landscapes of an urban park in Chengdu and determines the thermal benchmarks. A machine learning (random forest) analysis shows that human thermal sensation is affected by different meteorological factors in different seasons. In addition, the influences of landscape space on human thermal comfort have considerable differences in different seasons. Residents prefer strong solar radiation in winter but fast wind speed in summer. UTCI (universal thermal climate index) is better than PET (physiological equivalent temperature) for outdoor thermal comfort assessment in the study area. This study serves as a valuable baseline and technical reference, contributing to sustainable urban park design.

Groundwater discharge rates and uncertainties in a coastal lagoon using a radon mass balance

Coastal lagoons face anthropogenic pressures worldwide, and understanding groundwater discharge to these sensitive environments can enable better management of water budgets and nutrient inputs. The main objective of the study was to quantify groundwater seepage into a large and shallow coastal lagoon using a detailed radon (222Rn, a natural groundwater tracer) mass balance. To assess and reduce uncertainty, three wind-speed scenarios were modelled in two seasons using two 222Rn-in-groundwater endmembers. Groundwater discharge to the lagoon ranged between 5.2 ± 5.8 m3/s to 18.7 ± 19.6 m3/s during summer and 0.9 ± 2.2 m3/s to 8.1 ± 10.5 m3/s during winter. Wind-driven radon evasion was the most influential component of the radon mass balance. Higher summer wind speeds resulted in groundwater discharge estimates 3.5 times greater than those during winter. We carried out an in-depth uncertainty analysis of the radon mass balance results, which confirmed the importance of accounting for individual uncertainties, particularly the most sensitive parameters of the model. Overall, results from the radon mass balance revealed groundwater discharge to the lagoon was 1–2 orders of magnitude greater than previous localised seepage meter estimates. This is likely because radon tracer approaches quantify both one-directional discharge and bi-directional porewater exchange at a larger spatial scale than traditional seepage meter methods. In spite of large uncertainties, the possible range of reasonable estimates revealed groundwater seepage as an important component of the water budget at this site. This study highlights the benefits of broad-scale tracer-based mass balances for quantifying groundwater discharge to coastal lagoons and the value of in-depth uncertainty analysis to increase confidence in seepage flux estimates.

Microclimate characteristics in the famous dwellings: A case study of the Hakka Tulou in Hezhou, China

Hakka Tulou is a famous local earth construction, which is included in the UNESCO list of World Heritage buildings. To the best of our knowledge, there is a lack of thorough research into the microclimate characteristics of Hakka Tulou. In this study, we investigated the microclimate characteristics in the Hezhou Hakka Tulou. The indoor thermal sensation of the enclosure in warm circumstances was approximately equal to that of cool circumstances. However, the indoor thermal environment of Hakka Tulou could be improved by outer guard structures. In summer, the corridor structure allows for cooling down of the indoor air temperature, while the patio structure has the advantage of dehumidification. However, in winter, the building envelope has the advantages of thermal insulation and moisture-proofing. The location of higher wind speed in summer was mainly orientated from the center of the Hakka Tulou; however, this center appeared in the patio space. Such special environmental factors may be useful for the purpose of warmth in winter and coolness in summer. Furthermore, the patios of the Hakka Tulou effectively improved the lighting coefficient and illumination in the courtyard. However, the daylighting capacities of the inner rooms were considerably lower than those in the outer rooms.

Wind and Snow Loading of Balsam Fir during a Canadian Winter: A Pioneer Study

Widely distributed across Quebec, balsam fir (Abies balsamea (L.) Mill) is highly vulnerable to wind damage. The harsh winter conditions, freezing temperatures, and snow pose an additional risk. It is important to find the mechanical loads experienced by trees during winter to adapt forest management and minimize the risk of damage to this species. Many studies have been carried out on wind and snow loading damage risks in Northern Europe, mostly based on post-storm damage inventories. However, no study has continuously monitored the applied turning moment during a period with snow loading, and no study has investigated wind and snow loading on balsam fir. Therefore, our main objective was to conduct a pioneering study to see how trees bend under wind loading during winter, and to see how snow cover on the canopy contributes to the loading. Two anemometers placed at canopy height and 2/3 canopy height, air and soil temperature sensors, a hunting camera, and strain gauges attached to the trunks of fifteen balsam fir trees, allowed us to measure the wind and snow induced bending moments experienced by the trees together with the meteorological conditions. Data were recorded at a frequency of 5 Hz for more than 2000 h during summer 2018 and winter 2019. Two mixed linear models were used to determine which tree and stand parameters influence the turning moment on the trees and evaluate the effect of winter. The selected model for measurements made during winter found that including the snow thickness on crowns was better than those models that did not consider the effect of snow (ΔAICc &gt; 25), but the effect of snow depth on the bending moment appears to be minor. However, overall, the turning moment experienced by trees during winter was found to be higher than the turning moment experienced at the same wind speed in summer. This is probably a result of increases in the rigidity of the stem and root system during freezing temperatures and the change in wind flow through the forest due to snow on the canopy and on the ground during the winter season.

Robustness of the Recent Global Atmospheric Reanalyses for Antarctic Near-Surface Wind Speed Climatology

AbstractNear-surface wind speed observations from 30 manned meteorological stations and 26 automatic weather stations over the Antarctic Ice Sheet are used to examine the robustness of wind speed climatology in six recent global reanalysis products: the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), the Japan Meteorological Agency 55-Year Reanalysis (JRA-55), the Climate Forecast System Reanalysis (CFSR), the National Centers for Environmental Prediction–U.S. Department of Energy (DOE) Reanalysis 2 (NCEP2), and the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) and fifth-generation reanalysis (ERA5). Their skills for representing near-surface wind speeds vary by season, with better performance in summer than in winter. At the regional scale, all reanalysis datasets perform more poorly for the magnitude, but better for their year-to-year changes in wind regimes in the escarpment than the coastal and plateau regions. By comparison, ERA5 has the best performance for the monthly averaged wind speed magnitude and the interannual variability of the near-surface wind speed from 1979 onward. Intercomparison exhibits high and significant correlations for annual and seasonal wind speed Antarctic-wide averages from different datasets during their overlapping timespans (1980–2018), despite some regional disagreements between the different reanalyses. Furthermore, all of the reanalyses show positive trends of the annual and summer wind speeds for the 1980–2018 period, which are linked with positive polarity of the southern annular mode.

Numerical study and in-situ measurement of temperature features of asphalt supporting layer in slab track system

Recently, asphalt supporting layer (ASL) has been adopted as a novel technology to waterproof subgrade and increase stability of slab track in China. Asphalt concrete is a typical thermal sensitive material and its mechanical properties are very susceptible to temperature conditions, which makes it very brittle at low temperature and easy to suffer from deformation at high temperature. Therefore, it is essential to investigate the temperature features of ASL in slab track during its service life. In this paper, the temperature distribution within ASL was studied by combining field recorded data and numerical simulation, and the effects of meteorological factors including air temperature, solar radiation, and wind speed were numerically studied with emphasis. The results show that the temperature within ASL distributed non-uniformly along the cross section of ASL, and the temperature of the area directly underneath the track slab was much more stable than other areas exposed to the air. The variation of meteorological factors including air temperatures, solar radiation and wind speed has significant effects on the temperature of ASL, but it takes hours for the change of meteorological factors to be seen within ASL. There is alinear relation between the change of ASL temperature and the variation of air temperature and solar radiation incident, but the influence of wind speed decreases with the increasing of wind speed. Meanwhile, the temperature of ASL is moresusceptible to solar radiation and wind speed in summer, and it is more easily affected by air temperature in summer.

Field Study on the Microclimate of Public Spaces in Traditional Residential Areas in a Severe Cold Region of China.

As residential environment science advances, the environmental quality of outdoor microclimates has aroused increasing attention of scholars majoring in urban climate and built environments. Taking the microclimate of a traditional residential area in a severe cold city as the study object, this study explored the influence of spatial geometry factors on the microclimate of streets and courtyards by field measurements, then compared the differences in microclimate of distinct public spaces. The results are as follows. (1) The temperature of a NE-SW (Northeast-Southwest) oriented street was higher than that of a NW-SE (Northwest-Southeast) oriented street in both summer and winter, with an average temperature difference of 0.7–1.4 °C. The wind speeds in the latter street were slower, and the difference in average wind speed was 0.2 m/s. (2) In the street with a higher green coverage ratio, the temperature was much lower, a difference that was more obvious in summer. The difference in mean temperature was up to 1.2 °C. The difference in wind speed between the two streets was not obvious in winter, whereas the wind speed in summer was significantly lower for the street with a higher green coverage ratio, and the difference in average wind speed was 0.7 m/s. (3) The courtyards with higher SVF (sky view factor) had higher wind speeds in winter and summer, and the courtyards with larger SVF values had higher temperatures in summer, with an average temperature difference of 0.4 °C. (4) When the spaces had the same SVF values and green coverage ratios, the temperature of the street and courtyard were very similar, in both winter and summer. The wind speed of the street was significantly higher than the courtyard in summer, and the wind speed difference was 0.4 m/s.

Seasonal Variability of Wind Sea and Swell Waves Climate along the Canary Current: The Local Wind Effect

A climatology of wind sea and swell waves along the Canary eastern boundary current area, from west Iberia to Mauritania, is presented. The study is based on the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis ERA-Interim. The wind regime along the Canary Current, along west Iberia and north-west Africa, varies significantly from winter to summer. High summer wind speeds generate high wind sea waves, particularly along the coasts of Morocco and Western Sahara. Lower winter wind speeds, along with stronger extratropical storms crossing the North Atlantic sub-basin up north lead to a predominance of swell waves in the area during from December to February. In summer, the coast parallel wind interacts with the coastal headlands, increasing the wind speed and the locally generated waves. The spatial patterns of the wind sea or swell regional wave fields are shown to be different from the open ocean, due to coastal geometry, fetch dimensions, and island sheltering.

Seasonal variability in winds in the north polar region of Mars

Surface features near Mars’ polar regions are very active, suggesting that they are among the most dynamic places on the planet. Much of that activity is driven by seasonal winds that strongly influence the distribution of water ice and other particulates. Morphologic features such as the spiral troughs, Chasma Boreale, and prominent circumpolar dune fields have experienced persistent winds for several Myr. Therefore, detailing the pattern of winds throughout the year is an important step to understanding what processes affect the martian surface in contemporary and past epochs. In this study, we provide polar-focused mesoscale simulations from northern spring to summer to understand variability from the diurnal to the seasonal scales. We find that there is a strong seasonality to the diurnal surface wind speeds driven primarily by the retreat of the seasonal CO2 until about summer solstice, when the CO2 is gone. The fastest winds are found when the CO2 cap boundary is on the slopes of the north polar layered deposits, providing a strong thermal gradient that enhances the season-long katabatic effect. Mid-summer winds, while not as fast as spring winds, may play a role in dune migration for some dune fields. Late summer wind speeds pick up as the seasonal cap returns.

Long‐term austral summer wind speed trends over southern Africa

ABSTRACTA comprehensive analysis of near surface (10‐m and 850 hPa) long‐term (1980–2015) austral summer mean wind speed trends over southern Africa and the surrounding oceans (10°–40°S and 10°W‐50°E) is carried out. The climate forecast system reanalysis and the climate forecast system reanalysis version 2, the modern era retrospective‐analysis for research and applications version 2, and the ERA‐Interim products are used for the analysis. Trends are estimated using the Theil–Sen slope estimator and their significance tested with the Mann–Kendall test. Attribution of the wind speed trends to large scale circulation systems is determined from: (1) trends in 850 hPa geopotential height, surface pressure, and surface skin temperatures, (2) changes in the annual frequency of archetypal synoptic states generated by self‐organizing maps from geopotential height data, and (3) the correlations of the wind speeds to the southern annular mode (SAM) and El Niño Southern Oscillations (ENSO) indices. There is an overall decline in wind speeds evident in all the reanalyses. Wind speeds reduce by an average 0.7 and 1.3 m s−1 at 10 m and 850 hPa, respectively, over the study period. Deceleration in midlatitude westerly and Atlantic south easterly winds are associated with a poleward shift in the subtropical anticyclone, a positive trend in the annual frequency of summer circulation weather types, and the weakening of the subtropical continental heat low. The SAM and ENSO are also found to have a statistically significant linear association with the observed wind speed trends.

The contribution of physical processes to inter‐annual variations of hypoxia in Chesapeake Bay: A 30‐yr modeling study

A numerical circulation model with a very simple representation of dissolved oxygen dynamics is used to simulate hypoxia in Chesapeake Bay for the 30-yr period 1984–2013. The model assumes that the biological utilization of dissolved oxygen is constant in both time and space in an attempt to isolate the role that physical processes play in modulating oxygen dynamics. Despite the simplicity of the model it demonstrates skill in simulating the observed inter-annual variability of hypoxic volume, capturing 50% of the observed variability in hypoxic volume (<2 mg L−1) for the month of July and 58% of the observed variability for the month of August, over the 30-yr period. Model skill increases throughout the summer suggesting that physical processes play a more important role in modulating hypoxia later in the summer. Model skill is better for hypoxic volumes than for anoxic volumes. In fact, a simple regression based on the integrated January–June Susquehanna River nitrogen load can explain more of the variability in the observed anoxic volumes than the model presented here. Model results suggest that the mean summer (June–August) wind speed is the single-most important physical variable contributing to variations in hypoxic volumes. Previous studies have failed to document the importance of summer wind speed because they have relied on winds measured at Patuxent Naval Air Station, which does not capture the observed inter-annual variations in wind speed that are observed by stations that directly measure wind over the waters of Chesapeake Bay.