The relationship of the boundary layer of the magnetosphere to IPRP events

A model is proposed in which a mixture of hot solar wind and cold atmospheric plasma flowing in the dayside equatorial boundary layer towards the dawn-dusk plane generates hydromagnetic waves near the frequency $\text{ω = ω}{}_{\mathrm{Bi}}\text{¦1 ? T}{}_{\mathrm{\parallel }}\text{¦T}{}_{\mathrm{\perp }}\text{¦}$ where ω_Bi is the ion gyrofrequency and T_∥, T_⊥ are the temperatures of the solar wind plasma, parallel and perpendicular respectively to the magnetic field B. The model accounts for the properties of IPRP events, i.e. intervals of geomagnetic pulsations of periods rising on average from about 2 s to about 7 s over an interval of about 5 min. The diagnostic potential of this phenomenon for study of the boundary layer is indicated.     

Re‐evaluation of late Holocene fire histories of three boreal bogs suggest a link between bog fire and climate

We re‐evaluated mid‐ and late Holocene fire records at three bog sites in southern Finland and Estonia through quantitative and qualitative analysis of sedimentary charcoal records. Our analysis suggests synchrony amongst the Kontolanrahka, Männikjärve and Lakkasuo bog records. Over the last 5000 years, three episodes of elevated fire occurrence were evident in these bog records, taking place from 4500 to 4000, 3500 to 2000 and 1000 to 500 cal. a BP. These episodes were probably influenced primarily by climate, but also possibly by expansion/retreat of (pre)historic human populations. Although previous studies have proposed that during the late Holocene only weak fire?climate linkages exist, the presented analysis suggests millennial‐ and centennial‐scale synchronous burning episodes.     

The hydrocarbons in the Isla Vista marine seep environment

Hydrocarbon analyses on samples of sediment, interstitial water, and dissolved and particulate fractions of the water column from the vicinity of the Isla Vista seep near Santa Barbara, California, are presented. The results demonstrate that a very heterogeneous distribution of hydrocarbon composition and concentration exists in the seep environment and that the life-style and feeding habits of the organisms in this environment will have a dramatic effect on their hydrocarbon exposure.     

The missing soft X-ray luminosity in cluster cooling flows

The gas temperature in the cores of many clusters of galaxies drops inward by about a factor of 3 or more within the central 100-kpc radius. The radiative cooling time drops over the same region from 5 or more Gyr down to below a few 10⁸ yr. Although this indicates that cooling flows are taking place, XMM-Newton spectra show no evidence for strong mass cooling rates of gas below  1–2 keV  . The soft X-ray luminosity expected from steady cooling flows is missing. Here we outline and test the energetics of a cold mixing model in which gas below  1–2 keV  falls from the flow and is rapidly cooled by mixing with cold gas. The missing X-ray luminosity can emerge in the ultraviolet, optical and infrared bands, where strong emission nebulosities are commonly seen. We explore further the requirements for any heat sources that balance the radiative cooling in cluster cores.     

No detectable supernova remnant near the pulsar PSR 1930 + 22

No supernova remnant has been found near the third youngest pulsar PSR 1930+22 down to a -limiting brightness temperature of 1·4 K at 610 MHz. This is 6–8 times less than expected of a typical remnant whose age is that of the pulsar (3·60×10⁴ years).     

Study of nuclear decays during a solar eclipse: Thule Greenland 2008

A new prediction technique based on logarithmic values is proposed to predict the maximum amplitude (R _m) of a solar cycle from the preceding minimum aa geomagnetic index (aa _min). The correlation between lnR _m and lnaa _min (r=0.92) is slightly stronger than that between R _m and aa _min (r=0.90). From this method, cycle 24 is predicted to have a peak size of R _m(24)=81.7(1±13.2%). If the suggested error in aa (3 nT) before 1957 is corrected, the correlation coefficient between R _m and aa _min (r=0.94) will be slightly higher, and the peak of cycle 24 is predicted much lower, R _m(24)=52.5±13.1. Therefore, the prediction of R _m based on the relationship between R _m and aa _min depends greatly on the accurate measurement of aa.     

The role of land use on the local climate and air quality during calm inter-monsoon in a tropical city

The modification of land use is known to be a major climate change driver to the local warming and air quality in cities. Despite the reduction of NOx over the years, the Selangor state has captured a higher level of O_3 in year 2011. The measurement result has shown that the surge in O_3 level was attributed to the reduction of NO_x/NMHC ratio. This paper hence attempted to identify the role of land use change from 1999 to 2011 on the ground ozone air quality in the tropical urban conurbation, Greater Kuala Lumpur(GKL), Selangor, Malaysia. With the state-of-the-art chemical weather prediction tool, WRFChem, the external synoptic factors and emission inventory were controlled when comparing the chronological land use changes. The results showed that the urban-induced temperature and wind bias in the tropical region has induced stronger wind to disperse the NO_x and carries the TVOC from the suburban to the downwind urban region. The reduction of NO_x/TVOC has gradually shifted towards the optimum O_3 formation regime in 2011. The formation of highly concentrated ozone becomes more sensitive to the increment of TVOC as the NO_x level reduces in the urban. This highlights the essential involvement of TVOC in the ozone formation in lieu of the NOx reduction in the tropical city, a region with growing emitter of reactive biogenic ozone precursors.