On possible influence of space weather on agricultural markets: Necessary conditions and probable scenarios

We present the results of study of a possible relationship between the space weather and terrestrial markets of agricultural products. It is shown that to implement the possible effect of space weather on the terrestrial harvests and prices, a simultaneous fulfillment of three conditions is required: 1) sensitivity of local weather (cloud cover, atmospheric circulation) to the state of space weather; 2) sensitivity of the area-specific agricultural crops to the weather anomalies (belonging to the area of risk farming); 3) relative isolation of the market, making it difficult to damp the price hikes by the external food supplies. Four possible scenarios of the market response to the modulations of local terrestrial weather via the solar activity are described. The data sources and analysismethods applied to detect this relationship are characterized. We describe the behavior of 22 European markets during the medieval period, in particular, during the Maunder minimum (1650–1715). We demonstrate a reliable manifestation of the influence of space weather on prices, discovered in the statistics of intervals between the price hikes and phase price asymmetry. We show that the effects of phase price asymmetry persist even during the early modern period in the U.S. in the production of the durum wheat. Within the proposed approach, we analyze the statistics of depopulation in the eighteenth and nineteenth century Iceland, induced by the famine due to a sharp livestock reduction owing to, in its turn, the lack of foodstuff due to the local weather anomalies. A high statistical significance of temporal matching of these events with the periods of extreme solar activity is demonstrated. We discuss the possible consequences of the observed global climate change in the formation of new areas of risk farming, sensitive to space weather.     

Response of the Changjiang diluted water around Jeju Island to external forcings: A modeling study of 2002 and 2006

The Changjiang diluted water (CDW) around Jeju Island between 2002 and 2006 in response to external forcings, such as wind, tidal forcing and low river discharge, is studied using a three-dimensional model. The model results suggest that wind largely determines spatial differences of CDW and the freshwater export toward Jeju Island between two years. In 2006, when northwestward wind blows during mid June to mid August, the wind-induced Ekman flow causes a broad northeastward extension of CDW and carries a significant amount of freshwater northeastward Jeju Island in August. On the other hand, in 2002 northward wind during mid July to early August drives the CDW to the southwest of Jeju Island, and thereafter the CDW is mainly advected northeastward along the Cheju Current during mid August when the wind becomes weak. Therefore, the amount of freshwater around Jeju Island increases in September, not in August. The response to tidal forcing shows that tide-induced vertical mixing tends to enhance a meander of CDW around Changjiang Bank and shift the CDW flowing into the Yellow Sea southeastward toward Jeju Island. As a result, the amount of freshwater toward Jeju Island becomes larger than that in no-tides case. The summer low river discharge as a flood control scenario has little influence on the spatial behavior of CDW around Jeju Island although the discharge contributes to the amount of freshwater around Jeju Island.     

Mathematical modelling of historical reconnaissance CORONA KH-4B Imagery

This paper describes three mathematical modelling methods for high-resolution declassified CORONA KH-4B images. Since CORONA images are collected with a panoramic camera, several types of geometric distortions are involved. Two methods use the modified collinearity equations, and the third involves the terrain-dependent rational function model (RFM) which is considered to be a generic sensor model. Comparative analysis of the three mathematical modelling methods is undertaken. The results show that a ± 1·5 pixels level of horizontal and vertical accuracy can be obtained. A digital elevation model (DEM) of a test site is also created.     

Influence of solar activity on the state of the wheat market in medieval England

The database of professor Rogers (1887), which includes wheat prices in England in the Middle Ages, was used to search for a possible influence of solar activity on the wheat market. Our approach was based on the following: (1) Existence of the correlation between cosmic ray flux entering the terrestrial atmosphere and cloudiness of the atmosphere. (2) Cosmic ray intensity in the solar system changes with solar activity, (3) Wheat production depends on weather conditions as a nonlinear function with threshold transitions. (4) A wheat market with a limited supply (as it was in medieval England) has a highly nonlinear sensitivity to variations in wheat production with boundary states, where small changes in wheat supply could lead to bursts of prices or to prices falling. We present a conceptual model of possible modes for sensitivity of wheat prices to weather conditions, caused by solar cycle variations, and compare expected price fluctuations with price variations recorded in medieval England. We compared statistical properties of the intervals between wheat price bursts during the years 1249-1703 with statistical properties of the intervals between the minima of solar cycles during the years 1700-2000. We show that statistical properties of these two samples are similar, both for characteristics of the distributions and for histograms of the distributions. We analyze a direct link between wheat prices and solar activity in the 17^th century, for which wheat prices and solar activity data (derived from ¹⁰Be isotope) are available. We show that for all 10 time moments of the solar activity minima the observed prices were higher than prices for the corresponding time moments of maximal solar activity (100% sign correlation, on a significance level < 0.2%). We consider these results a direct evidence of the causal connection between wheat prices bursts and solar activity.     

4DVAR Data Assimilation with the Regional Ocean Modeling System (ROMS): Impact on the Water Mass Distributions in the Yellow Sea

In this study, we evaluate the performance of the recently developed incremental strong constraint 4-dimensional variational (4DVAR) data assimilation applied to the Yellow Sea (YS) using the Regional Ocean Modeling System (ROMS). Two assimilation experiments are compared: assimilating remote-sensed sea surface temperature (SST) and both the SST and in-situ profiles measured by shipboard CTD casts into a regional ocean modeling from January to December of 2011. By comparing the two assimilation experiments against a free-run without data assimilation, we investigate how the assimilation affects the hydrographic structures in the YS. Results indicate that the SST assimilation notably improves the model behavior at the surface when compared to the non-assimilative free-run. The SST assimilation also has an impact on the subsurface water structure in the eastern YS; however, the improvement is seasonally dependent, that is, the correction becomes more effective in winter than in summer. This is due to a strong stratification in summer that prevents the assimilation of SST from affecting the subsurface temperature. A significant improvement to the subsurface temperature is made when the in-situ profiles of temperature and salinity are assimilated, forming a tongue-shaped YS bottom cold water from the YS toward the southwestern seas of Jeju Island.     

Influence of solar activity on the state of the wheat market in medieval England

The database of professor Rogers (1887), which includes wheat prices in England in the Middle Ages, was used to search for a possible influence of solar activity on the wheat market. Our approach was based on the following: (1) Existence of the correlation between cosmic ray flux entering the terrestrial atmosphere and cloudiness of the atmosphere. (2) Cosmic ray intensity in the solar system changes with solar activity, (3) Wheat production depends on weather conditions as a nonlinear function with threshold transitions. (4) A wheat market with a limited supply (as it was in medieval England) has a highly nonlinear sensitivity to variations in wheat production with boundary states, where small changes in wheat supply could lead to bursts of prices or to prices falling. We present a conceptual model of possible modes for sensitivity of wheat prices to weather conditions, caused by solar cycle variations, and compare expected price fluctuations with price variations recorded in medieval England. We compared statistical properties of the intervals between wheat price bursts during the years 1249-1703 with statistical properties of the intervals between the minima of solar cycles during the years 1700-2000. We show that statistical properties of these two samples are similar, both for characteristics of the distributions and for histograms of the distributions. We analyze a direct link between wheat prices and solar activity in the 17^th century, for which wheat prices and solar activity data (derived from ¹⁰Be isotope) are available. We show that for all 10 time moments of the solar activity minima the observed prices were higher than prices for the corresponding time moments of maximal solar activity (100% sign correlation, on a significance level < 0.2%). We consider these results a direct evidence of the causal connection between wheat prices bursts and solar activity.     

Difference between the Lagrangian trajectories and Eulerian residual velocity fields in the southwestern Yellow Sea

The responses to tidal and/or wind forces of Lagrangian trajectories and Eulerian residual velocity in the southwestern Yellow Sea are investigated using a high-resolution circulation model. The simulated tidal harmonic constants agree well with observations and existing studies. The numerical experiment reproduces the long-range southeastward Eulerian residual current over the sloping bottom around the Yangtze Bank also shown in previous studies. However, the modeled drifters deployed at the northeastern flank of the Yangtze Bank in the simulation move northeastward, crossing over this strong southeastward Eulerian residual current rather than following it. Additional sensitivity experiments reveal that the influence of the Eulerian tidal residual currents on Lagrangian trajectories is relatively weaker than that of the wind driven currents. This result is consistent with the northeastward movement of ARGOS surface drifters actually released in the southwestern Yellow Sea. Further experiments suggest that the quadratic nature of the bottom friction is the crucial factor, in the southwestern Yellow Sea, for the weaker influence of the Eulerian tidal residual currents on the Lagrangian trajectories. This study demonstrates that the Lagrangian trajectories do not follow the Eulerian residual velocity fields in the shallow coastal regions of the southwestern Yellow Sea.     

Shifts in multi-decadal sea level trends in the East/Japan Sea over the past 60 years

Data derived from altimetry shows that since 1993 the mean sea level over the East /Japan (EJS) Sea is increasing at a rate of ~3 mm/year, but tide gauge records indicate that a multidecadal reversal trend occurred prior to the early 1980s. We here characterize and quantify the multi-decadal trend of mean sea level in the EJS from the reconstructed sea levels and the in-situ ocean profiles over the past 60 years. Our analysis shows that sea level trends have undergone a shift, revealing a declining trend before the early 1980s, followed by a rising trend from the early 1980s onward with a near basin-wide sea level fluctuation. The trend reversal strongly corresponds to changes in the upper-ocean heat content over the EJS, revealing a negative correlation with the Pacific Decadal Oscillation (PDO) index that correlates negatively with wind stress curl (WSC) in the subtropical North Pacific. The PDO-related WSC, which changes the transport of the western boundary current in the subtropical gyre, may account for the observed trend reversal in the EJS sea level on a multi-decadal time scale.