Pacific Ocean Area Research Articles

Potential control of climatic changes on flood events in the Yangtze Delta during 1100–2002

Wide collection on the historic records of the climatic changes and flood events is performed in the Yangtze Delta. Man-Kendall (MK) method is applied to explore the changing trends of the time series of the flood discharge and the maximum high summer temperature. The research results indicate that the flood magnitudes increased during the transition from the medieval warm interval into the early Little Ice Age. Fluctuating climate changes of the Little Ice Age characterized by arid climate events followed by the humid and cold climate conditions give rise to the frequent flood hazards. Low-lying terrain made the study region prone to the flood hazards, storm tide and typhoon. MK analysis reveals that the jumping point of the time series of the flood discharge changes occurred in the mid-1960s, that of the maximum summer temperature changes in the mid-1990s, and the exact jump point in 1993. The flood discharge changes are on negative trend before the 1990s, they are on positive tendency after the 1990s; the maximum high summer temperature changes are on negative trend before the 1990s and on positive tendency after the 1990s. These results indicate that the trend of flood discharge matches that of the maximum high summer temperature in the Yangtze Delta. The occurrence probability of the maximum high summer temperature will be increasing under the climatic warming scenario and which will in turn increase the occurrence probability of the flood events. More active solar action epochs and the higher sea surface temperature index (SST index) of the south Pacific Ocean area lying between 4°N-4°S and 150°W-90°W correspond to increased annual precipitation, flood discharge and occurrence frequency of floods in the Yangtze Delta. This is partly because the intensified solar activities and the higher SST index give rise to accelerated hydrological circulation from ocean surface to the continent, resulting in increased precipitation on the continent.

Assessment of wintertime atmospheric pollutants in an urban area of Kansai, Japan

Abstract An intensive measurement of particulate matter and gaseous materials was made to assess the characteristics of wintertime atmospheric pollutants in an urban area of Kansai, Japan. Sampling was performed by a combination of filter pack sampler and low-pressure Andersen impactor (LPAI). Particle-induced X-ray Emission (PIXE) and Thermal/Optical Reflectance (TOR®) methods were employed in analyzing element and carbon, respectively. The concentrations of SO2, NOx, and PM2.5 monitored during our intensive measurement show a strong time serial variation. PM2.5 levels are higher in the daytime with an average level of 21.3 μg m−3. Most of the peaks for NOx were regularly found in the morning throughout the campaign duration. The number concentration of particles larger than 0.3 μm appears dominated by the ultrafine particles ranged between 0.3 and 0.5 μm. The size distribution of elemental concentration as a function of water solubility was investigated. Organic carbon (OC) concentration shows the strong size distribution with the main peak formed in a range of 0.29–0.67 μm, while elemental carbon (EC) is principally enriched in a range of 0.12–0.29 μm ultra fine fraction. TC (OC+EC) fraction accounts for 42.5% and 26.2% of the mass concentration in fine particle fraction ( 1.17 μm), respectively. The simulated backward aerosol dispersion with the surface wind roses for three events of high PM2.5 mass concentration indicates that aerosol dispersions might be originated from the emission sources of Osaka and Shiga. Also the possibility of long-range transportation of fine particulate matter from the domestic areas of Japan, Taiwan, and Pacific Ocean was still raised. The result of factor analysis indicates that automobile exhaust, fossil fuel combustion, refuse incineration, iron industry, and soil originated particles contribute the major portion of PM2.5 in our sampling area.

Altimeter observations of sea-level variability off the west coast of North America

A combination of careful harmonic analysis and high-resolution numerical modelling of tides in altimeter data from TOPEX/Poseidon and ERS-2 satellites allows detailed calculation of seasonal and interannual variability of sea level in coastal areas of the north-east Pacific Ocean. These calculations show large changes in sea level in marginal seas during the 1997–8 El Niño and La Niña events, as well as providing information on the origin and life cycle of large anticyclonic eddies, observed to be generated off the west coast of Canada.

A study of the stationary and the anomalous in the ocean surface chlorophyll distribution by satellite data

Variability of chlorophyll concentration in the ocean is one of the most important components of the primary production process on the planet. To preserve the biosphere and to make appropriate use of it, it is imperative to have a deep insight into the long-term dynamics of the primary production on the planet. To investigate the dynamics of chlorophyll concentration based on satellite data, the Institute of Biophysics (Russian Academy of Sciences, Siberian Branch) has developed a geoinformation system. It was used to detect the areas in the global ocean that are quasistationary in relation to seasonal dynamics of chlorophyll concentration. Areas such as these, found in the Indian Ocean, are described in this work. These areas form the basis for the analysis of long-term dynamics of chlorophyll concentration. In these quasistationary zones systematic monitoring of phytopigment concentration is conducted by space-borne and marine craft. The work presents long-term satellite-based data on the space distribution of anomalous deviations of chlorophyll concentration in the ocean. An anomaly criterion is proposed and maps of Pacific Ocean areas with a high probability of anomalies are presented.

Distribution and Characteristics of Mesoscale Cyclones in the Antarctic: Ross Sea Eastward to the Weddell Sea*

The mesoscale cyclone activity observed in the portion of Antarctica that faces the South Pacific Ocean and Weddell Sea area is summarized from a study of 1991. In general, area-normalized results reveal much greater mesoscale cyclonic activity over the Ross Sea/Ross Ice Shelf and southern Marie Byrd Land than on both sides of the Antarctic Peninsula. More than 50% of the observed mesoscale vortices are of the comma cloud type. The average diameter of mesoscale vortices is approximately 200 km near Terra Nova Bay, 270 km near Byrd Glacier, and 280 km near Siple Coast. Near the Antarctic Peninsula, the average diameter is about 370 km over the Bellingshausen Sea and 380 km on the Weddell Sea side. The largest percentage of deep vortices occurs over the Bellingshausen Sea sector (38% of all cases), where convective instability frequently occurs. Over the Ross Sea/Ross Ice Shelf and Weddell Sea sectors the majority of the mesoscale vortices are low cloud features that probably do not exceed the 700-hPa level due to the prevailing lower-atmospheric stability. The areas identified as sources of mesoscale vortices concur with the locations of enhanced katabatic winds. A synthesis of the available literature leads to some general characteristics of mesoscale cyclone formation and development. Mesoscale cyclogenesis is associated with areas of warm and/or cold air advection, low-level baroclinicity, and cyclonic vorticity resulting from the stretching mechanism. Subsequent intensification depends on the presence of upper-level support. Spatial and temporal variability in mesoscale cyclone formation is often related to the behavior of synoptic-scale cyclone tracks. Mesoscale cyclones can generate precipitation and severe weather conditions and thus present a critical forecasting challenge.

Annual and seasonal trends in chemical composition of precipitation in Japan during 1989–1998

Annual and seasonal trends were discussed for precipitation chemistry in Japan on the basis of a nationwide monitoring network by Japan Environment Agency. For this analysis, 17 sites, selected from the 23 network sites after evaluation of data completeness for the present purpose, were grouped into four areas in terms of the sea which could characterize each area: the Pacific Ocean, the Japan Sea, the Seto Inland Sea and the East China Sea areas. Major ion concentrations at each site were subjected to least-squares multiple regression analysis, and discussion was principally focused on the area-groups. Each area showed significant ( p<0.05) decreasing trends in non-sea-salt sulfate (nss-SO 4 2−) concentrations with the annual mean change rate of −3.0% yr −1, whereas no significant trends were detected for NO 3 − at 59% of the sites. Ammonium (NH 4 +) showed significant increasing trends for 35%, and decreasing trends for 18% of the sites; and, the maximum change rate of 3.8% yr −1 was recorded in the Pacific Ocean area. Non-sea-salt calcium (nss-Ca 2+) concentrations significantly decreased in northern and some industrialized areas. Both the annual cycle-amplitudes and effects of precipitation amounts were significant for the four ions at almost all sites. The maximum concentrations of nss-SO 4 2− and -Ca 2+ occurred from winter to spring at most sites. The seasons when the maximum concentrations of NO 3 − and NH 4 + occurred, were found to differ from area to area. Furthermore, the trends in precipitation nss-SO 4 2−, and NO 3 − were qualitatively consistent with those of anthropogenic emissions of SO 2, and NO x in Japan, respectively.

The use of atmospheric relative angular momentum to diagnose the Arctic oscillation

Recent studies suggest that the North Atlantic Oscillation is a regional expression of the Northern Hemisphere Annular Mode. However, the lack of an apparent link between Atlantic and Pacific sectors questions the annular paradigm. In any case, the phenomenon is the largest and most fundamental mode of variability in the Northern Hemisphere troposphere, being responsible for much of the warming in the Northern Hemisphere surface temperature. The main aim of this study is to diagnose the Northern Hemisphere Annular Mode using an annular magnitude, such as the relative angular momentum (RAM). RAM from 500 hPa to 200 hPa is computed for the polar cap, using 60° longitude sectors as well as the whole cap, from 55 to 90°N and for the period 1958–1998, using NCEP-NCAR reanalysis data. Annual values of RAM are then correlated to temperature and geopotential height at 200, 500 and 850 hPa. The Artic region is dominated by very negative correlations for the Northern Hemisphere RAM and for the six different RAM sectors. Midlatitudes are dominated by positive correlation, with intermittent or alternating significant regions not showing a regular annular pattern. The Pacific Ocean area is only significantly correlated with the Pacific RAM sector. Since an annular pattern is characterized by its hemispheric symmetry, two symmetric latitude rings are expected, but only the polar one is detected, the rest being incomplete. Due to the proximity of the grid points near the pole, which can lead to artificial zonal symmetry, all the calculations are repeated for RAM from 45 to 65°N, finding a similar pattern with lower correlations and less symmetry. So the results do not support the annular paradigm, understood as organized along latitude sectors, but a hemispheric dimension cannot be excluded.

Latitudinal comparisons of equatorial Pacific zooplankton

Abstract Zooplankton biomass and rates of ingestion, egestion and production in the equatorial Pacific Ocean along 140°W and 180° exhibit maximum values in the High-Nutrient Low-Chlorophyll (HNLC) zone associated with equatorial upwelling (5°S–5°N) as compared to the more oligotrophic regions to the north and south. Zooplankton biomass and rates are not usually highest on the equator, but increase “downstream” of the upwelling center as the zooplankton populations exhibit a delayed response to enhanced phytoplankton production. The vertical distribution of zooplankton biomass in the equatorial HNLC area tends to be concentrated in surface waters and is more uniform with depth in oligotrophic regions to the north and south of the equatorial upwelling zone. In general, the amount of mesozooplankton (>200 μm) carbon biomass is approximately 25% of estimated phytoplankton biomass and 30% of bacterial biomass in the HNLC area of the equatorial Pacific Ocean. Zooplankton grazing on phytoplankton is low in the equatorial Pacific Ocean, generally −1 for 64–200 μm zooplankton to 0.08 d −1 for 1000–2000 μm zooplankton. Thus, the numerical and functional response of equatorial zooplankton to increases in phytoplankton production are more rapid than normally occurs in sub-tropical and temperate waters. Potential zooplankton fecal pellet production, estimated from metabolic demand, is approximately 1.6 times the estimated gravitational carbon flux at 150 m in the zone of equatorial upwelling (5°S–5°N) and 1.1 times the export flux in the more oligotrophic regions to the north and south. The active flux of carbon by diel migrant zooplankton in the HNLC zone is a minor fraction of the gravitational flux (2% at 140°W, 4% at 180°) but increases in the more oligotrophic regions to the north and south where there is a deeper mixed layer and a greater relative proportion of diel migrant zooplankton.

ENSO drought onset prediction in northeast Brazil using NDVI

El Niño Southern Oscillation (ENSO) indices and satellite-recorded Normalized Difference Vegetation Index (NDVI) were used to construct a drought onset prediction model for northeast Brazil (NEB) using a multiple linear regression technique. Monthly NDVI and ENSO indices anomaly data for the period January 1981 to December 1993 were used to develop the model, while those of 1951 to 1998 were used to simulate the NDVI anomaly time series for model validation. Three different regression models were constructed using the NDVI anomaly as dependent variable and various ENSO indices anomalies including: Sea Surface Temperature in the Pacific Ocean area (5°N-5°S and 120°W-170°W, called Niño3.4), Southern Oscillation Index (SOI), North Atlantic Sea Surface Temperature (NATL), South Atlantic Sea Surface Temperature (SATL) and Dipole 2 (DIP2=SATL-NATL), as independent variables. Model 1 was constructed using 12-month NDVI data while Models 2 and 3 used data from only four months (September to December). The results showed that R 2 values of 0.38, 0.62 and 0.79 at a significance level of 1% were obtained for Model 1, Model 2 and Model 3 respectively. Simulated NDVI anomaly values agreed quite well with observed values for all three models but Model 3 had a better intensity estimate. The simulated dynamic evolution of the NDVI anomaly of 1951 to 1998 showed that the predicted NDVI anomalies coincided with historical ENSO induced drought events reported in the literature. It is concluded that the use of satellite-recorded NDVI instead of rainfall data improved the correlation with ENSO indices. Drought onset Model 3, based on the dataset with high anomaly values of NDVI and ENSO indices, predicted drought onset in NEB four months before its occurrence with reasonable success (68%). Combined use of ENSO indices and NDVI inferred drought may provide a better alternative to the construction of an ENSO drought onset prediction model for other regions. Further studies will be carried out to investigate the ENSO drought and flood onsets in the southeastern South America.

Characteristics of the large-scale circulation changes during the sudden onset of the fall transition season

The characteristics of large-scale circulation changes manifest in the abrupt onset of the fall transition season are analysed for the Northern Hemisphere extratropical region. Ten years of daily observational data from the European Centre for Medium Range Weather Forecasts (ECMWF) global model initialization analyses are examined using the vertically integrated total kinetic energy (TKE) as the primary descriptor for circulation intensity. The time series data are bandpass filtered to examine subsets of frequencies representing specific atmospheric time scales, i.e. the low-frequency tropical forced oscillations (29.9–59.9 days), the intermediate-frequency oscillations related to non-linear processes such as weather regimes (10.0–29.7 days) and the high-frequency extratropical synoptic scale (2.5–6.5 days). Times when significant increases in kinetic energy (KE) variability occurred in the area-weighted hemispheric-mean time series for each bandpass were determined, and the onset date for each year and for each bandpass period was designated as the first significant increase in KE variability during the 1 August–30 November time period. Statistically significant abrupt onset events are found, with the majority occurring in August, September and October. The mean onset times vary from 3 October for the 29.9–59.9-day bandpass period to 30 August for the 2.5–6.5-day bandpass period. Composites with respect to the onset time show robust features of the abrupt onset event in both the hemispheric-mean time series and the spatial patterns of KE variability. Centres of maximum change in the magnitude of KE variability are in the western and central Pacific and the Atlantic Ocean sectors coincident with the areas of jet stream maxima. Separate analyses for onset characteristics for area-mean KE time series for the Pacific and Atlantic Ocean areas show that there is little correlation between Pacific and Atlantic onset times for the 29.9–59.9-day bandpass period. However, for the 10.0–29.7-day bandpass period the Atlantic onset times tend to lead the Pacific onset times, while for the 2.5–6.5-day bandpass period the Pacific region onset times tend to occur prior to the Atlantic onset times. Copyright © 2000 Royal Meteorological Society

Evaluation of bulk surface flux algorithms for light wind conditions using data from the Coupled Ocean-Atmosphere Response Experiment (COARE)

Five bulk surface flux formulae algorithms, currently used in large-and small-scale atmospheric and coupled ocean-atmosphere models, are tested with the same observations. Over the past decade many improvements have been made to the well-known bulk formulae used for estimating surface fluxes. This paper concentrates upon those improvements that have centred upon light wind conditions. This condition is especially important because light winds are often found in the equatorial zone of tropical oceans, particularly in the western Pacific Ocean area known as the Pacific warm pool. the Pacific warm pool is important to the maintenance of the general circulation of the atmosphere and to the initial phases of the El Niño Southern Oscillation (ENSO) phenomenon. the input data to the bulk algorithms are mean quantities of 15 m air temperature, moisture, wind velocity, and 2 cm depth sea surface temperature obtained by the RV Moana Wave during the Coupled Ocean-Atmosphere Response Experiment (COARE; 1 November 1992-28 February 1993). the output from the bulk formulae are tested against 15 m eddy correlation flux observations which were also part of the RV Moana Wave near-surface observational package. the RV Moana Wave was stationed in the Pacific warm pool for three periods during the COARE. Four formulae used exactly the same conditioning of the sea-surface-temperature input variable that was based upon upper ocean observations during the COARE. A surface renewal formulation had its own sea-surface-temperature adjustment scheme. the tests show that four of the five estimates of latent-heat flux magnitude are within 8% of observed values. For sensible heat, about 10% of the latent-heat flux magnitude, the range was 8-23%, and for momentum the range was 8-31% of observed values. Momentum flux was, as in the past, the most difficult to estimate. All approaches also used extensions to higher wind speeds. the test of those conditions was limited by a small dataset. It is shown that, for most of the algorithms tested, the bulk flux either overestimates or underestimates the covariance flux, depending upon the magnitude of the flux. In the COARE region this overestimation or underestimation is effectively a wind-speed dependent bias in the model due to the surface flux parametrization. an error analysis indicates that there may be substantial errors in the bulk flux due to instrument uncertainties in the inputs to the formula. These two conclusions have an important implication concerning deterministic atmospheric modelling. Chaos theory and other approaches to the accuracy-of-prediction problem show that small differences in the initial value (or nudging) of the deterministic predictive integration can lead to widely varying (but coherent) results. Since surface fluxes are a major input to atmospheric, ocean, and coupled models, the consequence of this effective bias error in surface flux, a bias-magnitude uncertainty due to natural variability, and errors associated with the inputs to surface flux parametrizations must be considered in determining the accuracy of deterministic models of the atmosphere and ocean. Otherwise the results of the integration, especially if long-term, when compared with the real atmosphere may have wide differences. From these considerations, it is suggested that current general-circulation models and climate models undergo surface flux sensitivity studies to test the effect of bias errors as discussed, and errors associated with inputs to the surface flux algorithms as well as natural variability.

Evaluation of bulk surface flux algorithms for light wind conditions using data from the coupled ocean‐atmosphere response experiment (COARE)

AbstractFive bulk surface flux formulae algorithms, currently used in large‐and small‐scale atmospheric and coupled ocean‐atmosphere models, are tested with the same observations. Over the past decade many improvements have been made to the well‐known bulk formulae used for estimating surface fluxes. This paper concentrates upon those improvements that have centred upon light wind conditions. This condition is especially important because light winds are often found in the equatorial zone of tropical oceans, particularly in the western Pacific Ocean area known as the Pacific warm pool. the Pacific warm pool is important to the maintenance of the general circulation of the atmosphere and to the initial phases of the El Niño Southern Oscillation (ENSO) phenomenon. the input data to the bulk algorithms are mean quantities of 15 m air temperature, moisture, wind velocity, and 2 cm depth sea surface temperature obtained by the RV Moana Wave during the Coupled Ocean‐Atmosphere Response Experiment (COARE; 1 November 1992‐28 February 1993). the output from the bulk formulae are tested against 15 m eddy correlation flux observations which were also part of the RV Moana Wave near‐surface observational package. the RV Moana Wave was stationed in the Pacific warm pool for three periods during the COARE. Four formulae used exactly the same conditioning of the sea‐surface‐temperature input variable that was based upon upper ocean observations during the COARE. A surface renewal formulation had its own sea‐surface‐temperature adjustment scheme. the tests show that four of the five estimates of latent‐heat flux magnitude are within 8% of observed values. For sensible heat, about 10% of the latent‐heat flux magnitude, the range was 8‐23%, and for momentum the range was 8‐31% of observed values. Momentum flux was, as in the past, the most difficult to estimate. All approaches also used extensions to higher wind speeds. the test of those conditions was limited by a small dataset. It is shown that, for most of the algorithms tested, the bulk flux either overestimates or underestimates the covariance flux, depending upon the magnitude of the flux. In the COARE region this overestimation or underestimation is effectively a wind‐speed dependent bias in the model due to the surface flux parametrization. an error analysis indicates that there may be substantial errors in the bulk flux due to instrument uncertainties in the inputs to the formula. These two conclusions have an important implication concerning deterministic atmospheric modelling. Chaos theory and other approaches to the accuracy‐of‐prediction problem show that small differences in the initial value (or nudging) of the deterministic predictive integration can lead to widely varying (but coherent) results. Since surface fluxes are a major input to atmospheric, ocean, and coupled models, the consequence of this effective bias error in surface flux, a bias‐magnitude uncertainty due to natural variability, and errors associated with the inputs to surface flux parametrizations must be considered in determining the accuracy of deterministic models of the atmosphere and ocean. Otherwise the results of the integration, especially if long‐term, when compared with the real atmosphere may have wide differences. From these considerations, it is suggested that current general‐circulation models and climate models undergo surface flux sensitivity studies to test the effect of bias errors as discussed, and errors associated with inputs to the surface flux algorithms as well as natural variability.

The Plankton and the Planet

In two dramatic experiments in 1996, iron was added to a large area of the tropical Pacific Ocean, causing a large phytoplankton bloom. This result not only demonstrated that (in at least some parts of the ocean) the lack of iron limits productivity, but also raised the possibility that fertilization of the ocean could increase its output. But how do we know where in the ocean to fertilize? In his Perspective, Mullineaux discusses an indicator of iron limitation (reported on p. 840 of this issue), which shows that iron is limiting productivity in unexpectedly large areas of the ocean.

Cool surface waters of the subtropical North Pacific Ocean during the last glacial

One of the most controversial results of the CLIMAP12 project's reconstruction of past sea surface temperature (SST) is that large areas of the subtropical Pacific Ocean were warmer during the last glacial period than they are today. This finding has important implications because SST patterns at low to subtropical latitudes strongly influence climate, and SST changes are closely linked with climate fluctuations3,4,5. Until now, a lack of well-preserved, high-resolution marine sediment cores from the region has hindered efforts to confirm these unexpectedly high ice-age SST estimates. Here we use both the oxygen-isotope compositions and species assemblages of planktonic foraminifera in a shallow-water core with high deposition rates near Hawaii to estimate glacial SST of the subtropical North Pacific Ocean. Contrary to the CLIMAP results2, our data indicate that the annual average SST in this region was ∼2 °C cooler during the last glaciation than it is today. These results help to reconcile the marine SST record with inferences drawn from snowline depressions on Hawaii during the last glacial3,6, and should ultimately yield improved estimates of global climate sensitivity by providing important new constraints on climate model simulations of ice-age cycles.

Space observations of ocean surface winds aid monitoring of Northeast Pacific climate shifts

Wind data from special sensor microwave imager (SSM/I) measurements indicate that winter climatic conditions along coastal areas of the northeast Pacific Ocean show pronounced interannual, month‐to‐month, and site‐to‐site variability. Site‐specific characterization is therefore needed to better understand conditions for different subregions. Analysis of surface winds and the relationship between wind direction and temperature anomalies is one option for achieving such characterization.Monitoring climatic conditions of these coastal areas is of special interest, since the northeast Pacific region undergoes periodic climatic shifts from cold‐and‐wet to warmand‐dry conditions and back again, and a shift to a cold‐and‐wet phase appears imminent. The study was motivated by Ingraham et al. [1998]. This earlier study is useful for detecting change. However, as a one‐parameter characterization, such change detection cannot adequately describe multisite climatic conditions for which separate and distinct information is required.

Elephant‐seal movements: Modelling migration

AbstractElephant seals migrate over vast areas of the eastern North Pacific Ocean between rookeries in southern California and distant northern foraging areas. Several models of particle movement were evaluated and a model for great‐circle motion found to give reasonable results for the movement of an adult female. This model takes specific account of the fact that the movement is on the surface of a sphere and that the animal is apparently heading toward a particular destination. The parameters of the motion were estimated. Such a great‐circle path of migration may imply that these seals have the ability to assess their position with respect to some global or celestial cues, allowing them to continually adjust their course and achieve the most direct geodesic route between origin and destination of migration. But the navigational mechanism actually used by these seals to accomplish such feats is as yet unknown.

Spatial Structure and Long-Term Variations of The Ground-Level Temperature Variance

The global distribution of the ground-level temperature variance and its long-term variations have been investigated on the basis of the monthly mean temperature anomalies, obtained from ground-based and sea-borne meteorological observations from 1896 to 1990. Particular characteristics of the large-scale structure of the temperature variance have been found. There are three pronounced maxima in the global distribution of the temperature variance: in Central Siberia (60°≤φ≤75°N and 70°≤λ≤ 120°E), North America (60°≤φ≤75°N and −170°≤λ≤−120°E) and the Antarctica (50°≤φ≤65°S and −60°≤λ≤10°E, where φ and λ are the geographic latitude and longitude, respectively) and there are two minima: over the Atlantic and Pacific Ocean areas. The minimum over the Pacific is not as pronounced, as over the Atlantic. The spatial pattern of the ground-level temperature variance is, on the whole, stable, the positions of the zones of extrema remaining practically unchanged over a long time interval. These results indirectly corroborate the mechanism of solar impact on the properties of the low atmosphere by the modulation of the flux of galactic cosmic rays. The mechanism accounts for the spatial distribution of the temperature variance as a result of combined effect of solar activity and ocean. Long-term variations of the Siberian maximum of the ground-level temperature variance agree with the changing duration of the sunspot cycle, in contrast to the North American maximum.

Teleconnective Response of the Pacific–North American Region Atmosphere to Large Central Equatorial Pacific SST Anomalies

Abstract A prominent year-round ensemble response to a global sea surface temperature (SST) anomaly field fixed to that for January 1992 (near the peak of a major warm El Nino–Southern Oscillation episode) was observed in a 20-yr integration of the general circulation model used for operational seasonal prediction by the U.S. National Weather Service. This motivated a detailed observational reassessment of the teleconnections between strong SST anomalies in the central equatorial Pacific Ocean and Pacific–North America region 700-hPa heights and U.S. surface temperatures and precipitation. The approach used consisted of formation of monthly mean composites formed separately from cases in which the SST anomaly in a key area of the central equatorial Pacific Ocean was either large and positive or large and negative. Extensive permutation tests were conducted to test null hypotheses of no signal in these composites. The results provided a substantial case for the presence of teleconnections to either the pos...

PCBS, DDE, DDT, and TCDD‐EQ in two species of albatross on Sand Island, Midway Atoll, North Pacific Ocean

AbstractConcentrations of total polychlorinated biphenyls (PCBs) and organochlorine insecticides, including the 1 1,1‐trichloro‐2, 2′‐bis‐p‐chlorophenyl‐ethane (DDT) complex, were measured in the plasma of chicks and adults and in eggs of Laysan albatrosses (Diomedea immutabilis) and black‐footed albatrosses (Diomedea nigripes) in a remote area of the central North Pacific Ocean. Significant differences in total concentrations of PCBs, DDT, and 1,1‐dichloro‐2,2′‐bis‐p‐chlorophenyl‐ethylene (DDE) in the plasma were detected between species and among sampling periods. Current concentrations of DDE in eggs of Laysan albatrosses are well below the threshold for eggshell thinning, based on the sensitivities of other fish‐eating birds, whereas concentrations of DDE in eggs of black‐footed albatrosses were approximately one‐half of the threshold concentrations necessary for eggshell thinning. The shells of Laysan and black‐footed albatross eggs are not currently exhibiting significant thinning that is resulting in population‐level effects. Current concentrations of PCBs are near those that could be having subtle population‐level effects in the black‐footed albatross, but not in the Laysan albatross. The hazard posed to the albatrosses by current concentrations of PCBs was assessed by calculating a hazard quotient (HQ), based on composite dose–response relationships for other species. Dioxin equivalents (TEq) based on mammalian toxic equivalency factors resulted in the greatest HQ, which was near the concentration when embryo lethality and deformities are observed in fish‐eating colonial waterbirds of the North American Great Lakes. Current concentrations of both PCBs and the DDT complex were similar to those in some species of piscivorous birds of the North American Great Lakes region.

アジア太平洋地域における水環境修復技術と国際協力

アジア太平洋地域における水環境修復技術と国際協力