Latitudinal Regions Research Articles

A new aspect of ionospheric E region electron density morphology

From global measurements of ionospheric electron density profiles made by the FORMOSAT‐3/COSMIC satellites, the morphology of E region electron density is investigated. Seasonal, latitudinal, and diurnal variations in daytime E region electron density are well described by the Chapman theory, and the E layer peak electron density NmE and its peak height hmE are governed by the solar zenith angle χ in accordance with relations NmE ∝(cosχ)p and hmE ∝ln(secχ), respectively. However, it is revealed that there are three geomagnetic latitude regions where striking enhancements of the E region electron density occur. One of them is located at the geomagnetic equator with relatively narrow latitude extent of about 6°–10°, and the other two with much wider latitude extent of about 10°–20° appear on both sides of the geomagnetic equator in latitude regions ±20°–30°, respectively. The locations of these E region density enhancements are asymmetrical about the geomagnetic equator in solstice seasons, and they have a salient tendency to shift toward (away from) the summer (winter) hemisphere. The off‐equator E region electron density enhancements are closely connected with the bottomside of the F region equatorial anomaly crests, where the component of the electron density parallel to the magnetic field line is maximum. It appears that the off‐equator E region electron density enhancements are very likely the footprints of the F region equatorial anomaly crests. The morphologies of the exponent n and coefficient K in the power law relation between χ and foE (E region critical frequency) are also examined. There is a tendency for the n and K values to be larger in local winter than in local summer seasons in the latitudinal regions the same as the off‐equator electron density enhancements. In addition, it is found that a minor peak in the K values is nearly continuously present in all seasons over the geomagnetic equator. A comparison shows significant discrepancies in the E region electron density morphologies between COSMIC measurement and IRI model prediction. Furthermore, compelling evidence is provided to show the presences of longitudinal wave number 3 and 4 structures of the electron density in the height region 100–200 km, which are in coincident with the longitudinal structures of equatorial electrojet. It is believed that these longitudinal 3‐ and 4‐peak structures are very likely associated with nonmigrating diurnal tides propagating eastward in ionospheric E region.

Transcontinental radio tomographic chain: First results of ionospheric imaging

The results of studying the structure of the ionospheric plasma distribution from data obtained at the transcontinental Russian radio tomographic chain, which is the world’s longest, are presented. The 4000 km long tomographic chain extends from the Svalbard Archipelago to Sochi. The unique feature of this upgraded radio tomographic system is that for the first time observations cover a wide sector of the ionosphere from high latitudes (polar cap and auroral region) to low latitudes. This allows us to study the transfer of perturbations in the system auroral-subauroral-midlatitude-low latitude ionosphere, and to analyze ionospheric electron density distributions in different latitudinal regions as a function of different external factors and solar-geophysical conditions. The first recent results speak for a complex structure of the ionospheric plasma, even in quiet geophysical conditions (Kp < 2.)

Middle Permian western Tethyan fusulinids from southern Baoshan Block, western Yunnan, China

New fusulinid collections from the Baoshan Block in southwest China necessitate paleobiogeographic reevaluation of the Mid-Permian fusulinids in this region. From Xiaoxinzhai Section in the southern Baoshan Block, 32 fusulinid species of nine genera are described and illustrated. Among them,Eopolydiexodina parvais a new species, and elements of Neoschwagerinidae and Verbeekinidae are confirmed. The studied fusulinids are ascendingly grouped into three biozones: theSchwagerina yunnanensisRange Zone,EopolydiexodinaAbundance Zone, andSumatrina annaeRange Zone. The lower two could be assigned in age to the Murgabian and the uppermost one to the Midian. Midian fusulinids are for the first time reported from the Baoshan Block. In terms of fusulinid paleobiogeography, these three assemblages should belong to the western Tethyan Province A because of the presence ofEopolydiexodinaand characteristic Tethyan genera, e.g.,Verbeekina, Sumatrina, and Pseudodoliolina.Moreover, these assemblages may occupy a comparatively high latitudinal region within Tethyan Realm, judging from the overall low diversity.

Atmospheric DDTs over the North Pacific Ocean and the adjacent Arctic region: Spatial distribution, congener patterns and source implication

During the 2003 Chinese Arctic Research Expedition (CHINARE 2003) from Bohai Sea to the high Arctic (37°N–80°N), air samples were collected and analyzed for DDTs. ∑DDTs (sum of six congeners) ranged from 0.52 to 265 pg m −3 with an average of 13.1 pg m −3. Higher DDT concentrations were observed in Bohai Sea and near eastern Russia. The congener patterns were obviously different between the Far East Asia and the higher latitudinal regions that p,p'-DDT and o,p'-DDT were dominated in the former; while o,p'-DDT and o,p'-DDE were dominated in the latter. The source contributions of technical DDT and dicofol type DDT were estimated. Results showed that technical DDT was the dominant source (>94%) which was fresher in the Far East Asia compared to the North Pacific Ocean and the Arctic. For dicofol type DDT, the estimated contribution was minor. The “new” o,p'-DDT observed should have relatively more contribution from dicofol type DDT in the North Pacific Ocean and the Arctic.

북서태평양에서 난수성(Pleuromamma sp.)과 냉수성(Neocalanus plumchrus) 요각류의 지방 함량 및 구성 분석을 통한 생리/생태 비교

In an effort to better understand the physiological and ecological differences between warm and cold water copepod species in Korean waters using lipid contents and compositions, two species of copepods (Pleuromamma sp. as a warm water species and Neocalanus plumchrus as a cold water species) were collected from the Northwest Pacific and East Sea/Sea of Japan, respectively. The cold water species showed two fold higher lipid contents than the warm water species (11% vs. 5% of dry weight). Wax esters, known as one of the major storage lipid classes, were found to be the dominant lipid class (accounting for 64% of total lipids) in the cold water species, whereas, in the warm water species, phospholipids, which are known as membrane components, were the dominant lipid class (accounting for 43% of total lipids),with a trace amount of the storage lipids as a form of triacylglycerols (<TEX>${\leq}1%$</TEX> of total lipids). With regard to the fatty acid compositions, saturated fatty acids (SAFA), especially 16:0 (about 30% of total fatty acids), were most abundant in the warm water species, whereas the polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA : 20:5(n-3)) (<TEX>${\geq}16%$</TEX> of total fatty acids), were most abundant in the cold water species. Among the neutral fraction of lipids, phytol, originating from the side chain of chlorophyll and indicative of active feeding on phytoplankton, was detected only in the warm water species. Significant quantities of fatty alcohols were detected in cold water species, particularly long-chain monounsaturated fatty alcohols (i.e. 20:1(n-9) and 22:1(n-11)), which are well known to abound in cold water herbivorous copepods. However, only trace amounts of short-chain fatty alcohols were detected in the warm water species. Twelve different kinds of sterols were detected in these copepod species, with cholest-5-en-<TEX>$3{\beta}$</TEX>-ol (cholesterol) and cholesta-5, 24-dien-<TEX>$3{\beta}$</TEX>-ol (desmosterol) dominating in cold and warm water species, respectively. In addition, for the warm water species (Pleuromamma sp.), we assessed the latitudinal gradients of lipid contents and compositions using samples from three different latitudinal regions (Philippine EEZ, Japan EEZ, and the East China Sea). Although no latitudinal gradients of lipid contents were detected, the lipid compositions, particularly dietary fatty acid markers, varied significantly with the latitude. The findings of this study confirm that the distribution of lipid contents and compositions in copepods may not only indicate their nutritional condition and diet history, but may also provide insights into their living strategies under different environmental conditions (i.e., water temperature, food availability).

Studying the change in fAPAR after forest fires in Siberia using MODIS

Disturbance events such as fire have major effects on forest dynamics, succession and the carbon cycle in the boreal biome. This paper focuses on establishing whether characteristic spatio‐temporal patterns of the fraction of Absorbed Photosynthetically Active Radiation (fAPAR) occur in the initial two years after a fire event in Siberian boreal forests. Time‐series of MODIS fAPAR were used to study post‐fire dynamics during the year of the fire and the following two years. Three forest types (evergreen needle‐leaf, deciduous needle‐leaf and deciduous broadleaf) grouped into three latitudinal regions, ranging from 51° N to 65° N, were studied by analysing a sample of 14 burned areas. For each of the burned areas an adjacent unburned control plot was selected with the aim of separating inter‐annual variations caused by climate from changes in fAPAR behaviour due to a burn. The results suggest that (i) the forest types exhibit characteristic fAPAR change trajectories shortly after the fire, (ii) the differences in the fAPAR trajectories are related to the forest type, (iii) fAPAR changes are not significantly different among the latitudinal regions, and (iv) the limited temporal variability observed among the 3 years of observations indicates that fAPAR varies very little in the initial years after a fire event.

Wegener’s granulomatosis: epidemiological and clinical features in a South Australian study

The epidemiology of Wegener's granulomatosis (WG) has shown a latitude-dependent predisposition in Northern Hemisphere and in New Zealand. There are no studies describing epidemiology or long-term follow up of WG reported from Australia. The aims of this study were to describe the epidemiological and clinical features of WG in South Australia (SA). The 5-year incidence of WG in SA over the period 2001-2005 was determined using the International Classification of Diseases classification (M313) of the discharge diagnosis using the Integrated South Australian Activity Collection. A retrospective case record analysis of 30 patients fulfilling the American College of Rheumatology criteria for WG and managed at two regional hospitals over a 20-year period (1985-2004) was carried out. The 5-year incidence of WG in SA was 56 per 10(6) (95% confidence interval 44.1-68.4 per 10(6)). There were no regional or seasonal variations in disease occurrence. The demographic, clinical and serological features in the clinical study were similar to previously published studies. Significant treatment-related morbidity was noted with 50% of patients having atherosclerotic vascular complications. The median survival was 12 years. There were two important periods with greater risk of dying -- in the first 5 years and after 10 years. The 5-year incidence of WG in SA is higher than that in the same latitudinal region in New Zealand ( approximately 34 degrees S). Atherosclerotic vascular disease was a major long-term morbidity. There is increased incidence of early mortality, warranting the need for earlier diagnosis and better therapies. Further studies from Southern Hemisphere are required for better epidemiological description of this disease.

Variability of the growth parameters of the skipjack tuna (Katsuwonus pelamis) among areas in the eastern Atlantic: analysis from tagging data within a meta-analysis approach

In order to assess the latitudinal variability in growth of the eastern Atlantic skipjack (Katsuwonus pelamis), conventional tagging data collected by the International Commission of the Conservation of Atlantic Tunas (ICCAT) since the 1960s are reanalyzed using a modified version of the von Bertalanffy-Fabens growth model. An analysis of the latitudinal patterns of recaptures showed that the lowest mixing rate between northern and southern regions was evidenced at 10° N Latitude. Since it is theoretically admitted that growth parameters L∞ and K are negatively correlated, we substituted L∞ into the growth equation model by a simple bioenergetic function of K fitted from existing studies on skipjack growth parameters. The likelihood for the meta-analysis of growth is combined with the likelihoods from the two regional tagging data with the aim of estimating simultaneously K in both areas and to transfer adequately uncertainties associated with the different data sets. From this study, it was showed that fish inhabiting waters south of 10° N latitude can be expected to grow generally larger but at slower rate than in the North (L∞ = 112.34 cm vs. 89.38 cm, and K = 0.14 vs. 0.38, respectively). Our results are consistent with the range of growth estimates obtained in the Atlantic Ocean and in different parts of the World's oceans. In contrast, the estimates of L∞ and K done in the Senegalese region in the 1980s within the framework of the Skipjack Year Program, and traditionally applied by ICCAT, are not supported by the present study. The findings concerning the phenotypic plasticity exhibited by growth of skipjack among latitudinal regions suggest potential differences in fish population productivity and consequently imply that non-conventional stock assessment methods such as catch-at size/growth transition matrix per region could be used to assess the responses of skipjack to exploitation.

Mediterranean marine copepods: basin-scale trends of the calanoid Centropages typicus

The Mediterranean Sea is located in a crossroad of mid-latitude and subtropical climatic modes that enhance contrasting environmental conditions over both latitudinal and longitudinal ranges. Here, we show that the large-scale environmental forcing is reflected in the basin scale trends of the adult population of the calanoid copepod Centropages typicus. The species is distributed over the whole Mediterranean basin, and maximal abundances were found in the north-western basin associated to oceanic fronts, and in the Adriatic Sea associated to shallow and semi enclosed waters. The peak of main abundances of C. typicus correlates with the latitudinal temperature gradient and the highest seasonal abundances occurred in spring within the 14–18°C temperature window. Such thermal cline may define the latitudinal geographic region where C. typicus seasonally dominates the >200 μm-sized spring copepod community in the Mediterranean Sea. The approach used here is generally applicable to investigate the large-scale spatial patterns of other planktonic organisms and to identify favourable environmental windows for population development.

Validation of stratospheric water vapour measurements from the airborne microwave radiometer AMSOS

Abstract. We present the validation of a water vapour dataset obtained by the Airborne Microwave Stratospheric Observing System AMSOS, a passive microwave radiometer operating at 183 GHz. Vertical profiles are retrieved from spectra by an optimal estimation method. The useful vertical range lies in the upper troposphere up to the mesosphere with an altitude resolution of 8 to 16 km and a horizontal resolution of about 57 km. Flight campaigns were performed once a year from 1998 to 2006 measuring the latitudinal distribution of water vapour from the tropics to the polar regions. The obtained profiles show clearly the main features of stratospheric water vapour in all latitudinal regions. Data are validated against a set of instruments comprising satellite, ground-based, airborne remote sensing and in-situ instruments. It appears that AMSOS profiles have a dry bias of 0 to –20%, when compared to satellite experiments. Also a comparison between AMSOS and in-situ hygrosondes FISH and FLASH have been performed. A matching in the short overlap region in the upper troposphere of the lidar measurements from the DIAL instrument and the AMSOS dataset allowed water vapour profiling from the middle troposphere up to the mesosphere.

Satellite‐derived variability in chlorophyll, wind stress, sea surface height, and temperature in the northern California Current System

Satellite‐derived data provide the temporal means and seasonal and nonseasonal variability of four physical and biological parameters off Oregon and Washington (41°–48.5°N). Eight years of data (1998–2005) are available for surface chlorophyll concentrations, sea surface temperature (SST), and sea surface height, while six years of data (2000–2005) are available for surface wind stress. Strong cross‐shelf and alongshore variability is apparent in the temporal mean and seasonal climatology of all four variables. Two latitudinal regions are identified and separated at 44°–46°N, where the coastal ocean experiences a change in the direction of the mean alongshore wind stress, is influenced by topographic features, and has differing exposure to the Columbia River Plume. All these factors may play a part in defining the distinct regimes in the northern and southern regions. Nonseasonal signals account for ∼60–75% of the dynamical variables. An empirical orthogonal function analysis shows stronger intra‐annual variability for alongshore wind, coastal SST, and surface chlorophyll, with stronger interannual variability for surface height. Interannual variability can be caused by distant forcing from equatorial and basin‐scale changes in circulation, or by more localized changes in regional winds, all of which can be found in the time series. Correlations are mostly as expected for upwelling systems on intra‐annual timescales. Correlations of the interannual timescales are complicated by residual quasi‐annual signals created by changes in the timing and strength of the seasonal cycles. Examination of the interannual time series, however, provides a convincing picture of the covariability of chlorophyll, surface temperature, and surface height, with some evidence of regional wind forcing.

Atmospheric Horizontal Resolution Affects Tropical Climate Variability in Coupled Models

Abstract The effect of atmospheric horizontal resolution on tropical variability is investigated within the modified Scale Interaction Experiment (SINTEX) coupled model, SINTEX-Frontier (SINTEX-F), developed jointly at Istituto Nazionale di Geofisica e Vulcanologia (INGV), L’Institut Pierre-Simon Laplace (IPSL), and the Frontier Research System. The ocean resolution is not changed as the atmospheric model resolution is modified from spectral resolution 30 (T30) to spectral resolution 106 (T106). The horizontal resolutions of the atmospheric model T30 and T106 are investigated in terms of the coupling characteristics, frequency, and variability of the tropical ocean–atmosphere interactions. It appears that the T106 resolution is generally beneficial even if it does not eliminate all the major systematic errors of the coupled model. There is an excessive shift west of the cold tongue and ENSO variability, and high resolution also has a somewhat negative impact on the variability in the east Indian Ocean. A dominant 2-yr peak for the Niño-3 variability in the T30 model is moderated in the T106 as it shifts to a longer time scale. At high resolution, new processes come into play, such as the coupling of tropical instability waves, the resolution of coastal flows at the Pacific–Mexican coasts, and improved coastal forcing along the coast of South America. The delayed oscillator seems to be the main mechanism that generates the interannual variability in both models, but the models realize it in different ways. In the T30 model it is confined close to the equator, involving relatively fast equatorial and near-equatorial modes, and in the high-resolution model, it involves a wider latitudinal region and slower waves. It is speculated that the extent of the region that is involved in the interannual variability may be linked to the time scale of the variability itself.

Ionospheric precursors observed at low latitudes around the time of koyna earthquake

On December 11, 1967 at 05:21 LT, an immense earthquake of magnitude 6.7 struck Koyna, the Indian province of Maharashtra. Its epicenter was located at geographic latitude 17.37°N and longitude 73.75°E with depth of about 3 km. Ground based measurements show variation in the critical frequency of ionospheric F2 layer (foF2) before and after the shock. In the present study the behavior of F2-region of ionosphere has been examined over the equatorial and low latitudinal region ionosphere during the month of December 1967 around the time of Koyna earthquake. For this purpose, the ionospheric data collected with the help of ground-based ionosondes installed at Hyderabad (located close to the earthquake epicenter) Ahmedabad, Trichirapulli, Kodaikanal and Trivendrum have been utilized. The upper and lower bound of Interquartile range (IRQ) are constructed to monitor the variations in foF2 other than day-to-day and diurnal pattern for finding the seismo-ionospheric precursors. Some anomalous electron density variations are observed between post midnight hours to local pre-noon hours at each station. These anomalies are strongly time dependent and appeared a couple of days before the main shock. The period considered in this study comes under the quiet geomagnetic conditions. Hence, the observed anomalies (which are more than the usual day-to-day variability) over all stations are likely to be associated with this imminent earthquake. The possible mechanism to explain these anomalies is the effect of seismogenic electric field generated just above the surface of earth within the earthquake preparation zone well before the earthquake due to emission of radioactive particles and then propagated upward, which perturbs the F-region ionosphere.

Contrail observations over Southern and Eastern Asia in NOAA/AVHRR data and comparisons to contrail simulations in a GCM

For the first time the contrail cover for a region covering Thailand and surrounding regions as well as for the region of Japan and its surroundings are determined by remote sensing observations. Locally received NOAA/AVHRR satellite data are analysed by a fully automated contrail detection algorithm. For both regions approx. 400 NOAA‐14 satellite scenes from four months of the year 1998 were analysed. Both regions show sufficient air traffic to produce an observable amount of contrails. Thus we are able to measure for the first time contrail frequencies in the tropics and compare it to a nearby mid latitudinal region. The annual average of the daily mean contrail cloud coverage is 0.13% for the Thailand region and about 0.25% for the Japan region. For both regions the contrail cover is largest during spring. The daily cycle shows surprisingly high contrail coverage during night in spite of lower air traffic densities during night time. The satellite observed contrail cover is compared with simulations of contrails by use of the general circulation model ECHAM4 related to air traffic emissions of 1992. While the derived patterns of the regional contrail distributions agree well, the contrail coverage derived from satellite data is larger than the simulated coverage. This discrepancy appears to be mainly due to an increase in air traffic in the time period between the model study and the observations.

Latitudinal Variation in Population Structure and Reproductive Pattern of the Endemic South American Shrimp Artemesia Longinaris (Decapoda: Penaeoidea)

Population structure and reproductive maturity of females were investigated in the shrimp Artemesia longinarisBate, 1888 from coastal waters of northern São Paulo State (Brazil, |$23^\circ {\rm{S}}$|⁠) and Mar del Plata (Argentina, |$38^\circ {\rm{S}}$|⁠) from June 2001 to May 2002. Monthly collections were taken by commercial shrimp fishing boats equipped with bottom trawl nets. Population parameters from size frequency distributions and size (carapace length = CL) of female reproductive maturity were analyzed and compared from the two sampling areas. Latitudinal trends in reproductive parameters of A. longinaris were shown in overall body size and size of reproductive maturity, both of which were smaller in females from the tropical location than those from the cold-temperate sampling area. Largest females |$( \gt \;30\;{\rm{mm}}\;{\rm{CL}})$| were collected in Argentina, while Brazilian specimens reached maximum size at |$27\;{\rm{mm}}\;{\rm{CL}}$|⁠. The smallest size of female sexual maturity was estimated at |$13.6\;{\rm{mm}}\;{\rm{CL}}$| in Brazilian samples compared to |$22.1\;{\rm{mm}}\;{\rm{CL}}$| calculated for those from Argentina. Populations from both regions exhibited a bimodal size distribution in the spring, with the peak at small body size probably corresponding to recent recruits and the peak at larger body size to reproductive females or shrimps migrating in from deeper waters or other latitudinal regions. In late spring and summer, an intrusion of the cold South Atlantic Coastal Water mass was observed which lowered water temperature and stimulated plankton production, the primary food source for the larvae of a typically cold-temperate species such as A. longinaris. The trend of increasing body size and delay of sexual maturity with increasing latitude appears to be correlated with the decreasing water temperature and increasing plankton productivity at higher latitudes.

A global statistical study on the origin of small‐scale ozone vertical structures in the lower stratosphere

We investigated meridional and seasonal variations in small‐vertical‐scale (wavelengths 0.5–3 km) fluctuations of the ozone mixing ratio in the lower stratosphere using ozonesonde data covering wide longitudinal and latitudinal regions in all seasons. The generation of mixing ratio fluctuation is attributed to vertical advection and/or horizontal advection; the former was estimated from the potential temperature fluctuation and the vertical gradient of background mixing ratio, while the latter was obtained by subtracting the vertical advection component from the observed value. The results show that horizontal advection is always the major source of the mixing ratio fluctuation above the potential temperature of 700 K (∼27 km altitude). Below 700 K, the source of the mixing ratio fluctuation depends on latitude; horizontal advection governs the mixing ratio fluctuations at high latitudes, vertical advection dominates at low latitudes, and horizontal advection is relatively dominant in winter–spring, while vertical advection is dominant in summer–autumn in the midlatitudes. These tendencies were confirmed by analyzing the correlation between the small‐scale structures of the mixing ratio and the potential temperature. The synthetic distribution of the horizontal advection activity due to synoptic‐scale motions calculated from assimilated meteorological data reproduced the seasonal, meridional, and altitudinal tendencies of the observed small‐scale fluctuations, suggesting the major contribution of differential advection via large‐scale winds.

Multiple field line resonances: Optical, magnetic and absorption signatures

We present multi-instrument observations of ultra low frequency (ULF) wave activity from the dawn flank magnetosphere during the period 12:00–13:30 UT on the 16 December 2003. Optical, magnetic and riometer measurements from the Churchill line meridian in the Canadian sector are presented which demonstrate the presence of multiple discrete auroral arc structures accompanied by periodic magnetic and riometer absorption perturbations in the Pc5 (150–600 s) ULF band. Clear polewards propagation is demonstrated in all the instrument data sets, the magnetic signals showing most clearly the amplitude and phase characteristics consistent with discrete frequency field line resonances (FLRs) on closed field lines. Two discrete frequency field line resonant signals are apparent, at 1.8 and 3.0 mHz which resonate at approximately the same latitude. We explain this via the calculation of the Alfvén continuum, and show that both frequencies may be resonant in the same latitudinal region within instrumental resolution. The meridian scanning photometer (MSP) observations from polewards of the magnetometer determined resonant latitudes show evidence of low intensity (∼200 R) poleward moving discrete arcs related to the ULF waves. Interestingly the MSP observations demonstrate poleward phase propagation with variable rates across the field of view; faster apparent polewards phase propagation being seen at higher latitudes. We demonstrate that the complicated “braided” phase of the arcs can be explained via the precipitation resulting from the superposition of two discrete FLRs. Furthermore, we characterise the ≳25 keV energetic electron precipitation in the region of the FLRs and the arc structures via periodic D-region absorption. In this way, we link the magnetic and both soft and energetic particle precipitation signatures of FLRs together for the first time. Our results demonstrate that riometer absorption can be used to characterise FLRs, however, this is only generally possible at lower L-shells where energetic electrons in the ring current overlap with the FLR fields in the equatorial plane.

Modeling of the seasonal effects of geomagnetic storms in the eastern Asian ionosphere

in the ionospheric response to a geomagnetic storm are obtained depending on latitude and season. At middle latitudes the most interesting is that the positive and negative phases of ionospheric disturbance prevail in winter and summer, respectively. To interpret the observed variations in the ionospheric structure, modeling is performed, using a theoretical ionospheric model. The analysis of the processes governing the response of the midlatitude ionosphere to a geomagnetic storm showed a good agreement between the results of modeling and measurements and made it possible to detect the determining role of the neutral composition in the observed variations in ionospheric parameters. At auroral and subauroral stations the variability of the electron concentration during a storm is much better pronounced. According to the results of the analysis of the trajectories of the ionospheric plasma convection, this variability is caused by the joint action of the convection and energetic electron precipitations. The disturbances in the neutral composition in this latitudinal region influence the background electron concentration level. INDEX TERMS: 2441 Ionosphere: Ionospheric storms; 2447 Ionosphere: Modeling and forecasting; 2407 Ionosphere: Auroral ionosphere; KEYWORDS: Ionospheric storms; Ionosphere-magnetosphere interactions; Numerical simulations.

Distributions of particulate and dissolved organic and inorganic phosphorus in North Pacific surface waters

Several operationally defined fractions of phosphorus (P) were measured along a surface water transect in the North Pacific. The P content in all fractions was found to increase northward from the edge of the subtropical to the subarctic region. Particulate organic P (POP) concentrations increased from 9 to 110 nmol L − 1 , whereas the particulate inorganic P (PIP) concentrations increased from 1 to 13 nmol L − 1 . A significant correlation between POP, PIP and chlorophyll a suggested that these P pools are associated directly or indirectly with phytoplankton cells. PIP comprised 10–20% of the total particulate P pool across the transect, indicating it is an important component of the marine P cycle in this region. Dissolved non-reactive P (assumed to consist predominantly of non-reactive organic P compounds, thus referred to as DOP) concentration increased from 0.10 to 0.22 μmol L − 1 , whereas soluble reactive P (SRP) concentration increased from 0.01 to 1.42 μmol L − 1 along the transect. The proportion of DOP and SRP varied widely, with a large proportion of DOP in areas with low total dissolved P concentrations in lower latitudes and a large proportion of SRP in areas with high total dissolved P concentrations in higher latitudes. High demand for DOP in the lower latitudinal region would diminish the concentration of this pool relative to higher latitudinal regions where SRP is more abundant and would be preferentially utilized. The availability of SRP could have a significant impact on the concentration and probably on the composition of DOP. We show that P fractionation provides an important insight for discussing the marine P cycle.

Mediated Modeling of the Impacts of Enhanced UV‐B Radiation on Ecosystem Services

This article describes the use of group model building to facilitate interaction with stakeholders, synthesize research results and assist in the development of hypotheses about climate change at the global level in relation to UV-B radiation and ecosystem service valuation. The objective was to provide a platform for integration of the various research components within a multidisciplinary research project as a basis for interaction with stakeholders with backgrounds in areas other than science. An integrated summary of the scientific findings, along with stakeholder input, was intended to produce a bridge between science and policymaking. We used a mediated modeling approach that was implemented as a pilot project in Ushuaia, Argentina. The investigation was divided into two participatory workshops: data gathering and model evaluation. Scientists and the local stakeholders supported the valuation of ecosystem services as a useful common denominator for integrating the various scientific results. The concept of economic impacts in aquatic and marsh systems was represented by values for ecosystem services altered by UV-B radiation. In addition, direct local socioeconomic impacts of enhanced UV-B radiation were modeled, using data from Ushuaia. We worked with 5 global latitudinal regions, focusing on net primary production and biomass for the marine system and on 3 plant species for the marsh system. Ecosystem service values were calculated for both sectors. The synthesis model reflects the conclusions from the literature and from experimental research at the global level. UV-B is not a significant stress for the marshes, relative to the potential impact of increases in the sea level. Enhanced UV-B favors microbial dynamics in marine systems that could cause a significant shift from primary producers to bacteria at the community level. In addition, synergetic effects of UV-B and certain pollutants potentiate the shift to heterotrophs. This may impact the oceanic carbon cycle by increasing the ratio of respiratory to photosynthetic organisms in surface waters and, thus, the role of the ocean as a carbon sink for atmospheric CO2. In summary, although changes in the marine sector due to anthropogenic influences may affect global climate change, marshes are expected to primarily be affected by climate change.