A conjugate study of the polar ionospheric F2-layer and IRI-2007 at 75 ° magnetic latitude for solar minimum

Long-duration conjugate observations by the EISCAT Svalbard Radar （ESR） and the ionosonde at Zhongshan station from the International Polar Year （IPY） during solar minimum conditions are analyzed, with respect to variability in the F2-1ayer peak parameters. A comparison between International Reference Ionosphere- 2007 （IRI-2007） and observation data clearly demonstrates good agreement in summer, but greater deviations in winter. The IRI model reproduces the F2 peak parameters dominated by solar photoionization reasonably well, but it does not address the effect of electron precipitation. Hence, the discrepancies become large in the winter auroral ionosphere.

The Approaching New Grand Solar Minimum and Little Ice Age Climate Conditions

By about 2030-2040, the Sun will experience a new grand solar minimum. This is evident from multiple studies of quite different characteristics: the phasing of sunspot cycles, the cyclic observations of North Atlantic behaviour over the past millennium, the cyclic pattern of cosmogenic radionuclides in natural terrestrial archives, the motions of the Sun with respect to the centre of mass, the planetary spin-orbit coupling, the planetary conjunction history and the general planetary-solar-terrestrial interaction. During the previous grand solar minima—i.e. the Sporer Minimum (ca 1440-1460), the Maunder Minimum (ca 1687-1703) and the Dalton Minimum (ca 1809-1821)—the climatic conditions deteriorated into Little Ice Age periods.

Comparative analysis of extreme ultraviolet solar radiation proxies during minimum activity levels

Four extreme ultraviolet(EUV)solar radiation proxies(Magnesium II core-to-wing ratio(MgII),Lymanαflux(Fα),10.7-cm solar radio flux(F10.7),and sunspot number(Rz))were analyzed during the last four consecutive solar activity minima to investigate how they differ during minimum periods and how well they represent solar EUV radiation.Their variability within each minimum and between minima was compared by considering monthly means.A comparison was also made of their role in filtering the effect of solar activity from the critical frequency of the ionospheric F2 layer,foF2,which at mid to low latitudes depends mainly on EUV solar radiation.The last two solar cycles showed unusually low EUV radiation levels according to the four proxies.Regarding the connection between the EUV“true”variation and that of solar proxies,according to the foF2 filtering analysis,MgII and Fαbehaved in a more stable and suitable way,whereas Rz and F10.7 could be overestimating EUV levels during the last two minima,implying they would both underestimate the inter-minima difference of EUV when compared with the first two minima.

Averaged NmF2 of cusp-latitude ionosphere in northern hemisphere for solar minimum—Comparison between modeling and ESR during IPY

Based on the ionosphere observation data obtained by EISCAT Svalbard Radar (ESR) in solar minimum year-2007, we analyzed diurnal variations of F2-peak electron density (NmF2) in four seasons under disturbed and quiet geomagnetic conditions. It indicated that the soft precipitation electron had an evident effect on the NmF2 increase at magnetic noon in spring, summer and autumn and the electron precipitation effects were prominent in winter. The comparison between the IRI-2007 model and the observation exhibited that the IRI (International Reference Ionosphere) model had a better NmF2 prediction when the photoionization was dominant during the polar day, but worse when the electron precipitation was dominant during the polar night. We showed that the electrons in lower energy band decreased when the geomagnetic disturbance went greater, which resulted in the lower NmF2. By analyzing the spectrum of precipitation electron under different geomagnetic conditions, it was found that this phenomenon was induced by the energy flux enhancement of precipitation electron of low energy.

Comparative Study of foF2 during Quiet Geomagnetic Activity with URSI and CCIR Predictions during the Phase Minimum of Solar Cycle 22

This paper investigates the performance of the latest International Reference Ionosphere model to predict the critical frequency at low latitudes in the African region. The variability of the critical frequency of the F2 layer of the ionosphere (foF2) is studied for the different seasons of the phase minimum of solar cycle 22 during quiet geomagnetic activity at the Ouagadougou station. The data used are those provided by the ionosonde and the predictions of the two subprograms: International Radio Consultative Committee (CCIR) and International Radio-Scientific Union (URSI) of the 2016 version of the International Reference Ionosphere model. This study shows that, in general, URSI and CCIR of the IRI-2016 model are able to reproduce fairly well the variability of the critical frequency of the F2 layer of the ionosphere at low latitudes during the phase minimum at the Ouagadougou station. However, the model shows an almost homogeneous overestimation of the foF2 during the four seasons studied. The good response is observed between 0700 TL and 1900 TL for the available data. The agreement between the subroutine responses and the observed results is between reasonable and poor. The best match state response is obtained in winter with the CCIR subroutine. These results show that there is a need to improve both CCIR and URSI subroutines of the IRI-2016 model in low latitudes in the African region.

The Additional Criterion for the Determination of the Time of Minimum of a Solar Cycle

The sunspot number is becoming an increasingly insufficiently reliable parameter for the determination of the time of minimum of a solar cycle during the prolonged and deep minimum of the 23rd solar cycle. Moreover, the sunspot number does not quantitatively reflect physical processes and is a practically conventional qualitative “noisy” parameter. Introduction of an additional criterion for the determination of the time of minimum of a solar cycle is becoming particularly topical due to the upcoming common descent of the level of the 2-secular cycle, when the amplitude of sunspot activity variation will sequentially decrease during several subsequent cycles (after the 23rd cycle). We propose the adoption of the smoothed minimal level of the total solar irradiance (TSI) as an additional physically justified criterion for the determination of the time of minimum of a solar cycle during the minimum of sunspot activity. The minimal level of the monthly average values of the TSI smoothed for 13 months when the last two of its values exceed the preceding value at the point of minimum will additionally indicate the time of minimum of a cycle. The additional criterion has been successfully used for the determination of the time of minima of the preceding 21st and 22nd cycles.

Effect of High-Speed Solar Winds Turbulence Upstream of the Earth’s Magnetosphere: Case of the Outer Minima of Solar Cycles 20, 21, 22, 23 and 24

Highly turbulent environment, the solar wind is a stream of very energetic particles mainly made of protons and electrons. During its trip in the interplanetary space, this solar flow becomes more accelerated during the outer minima (descending phases) of the solar cycles and can therefore influence all of humanity and its technology. These disturbances lead to socio-economic consequences requiring a precise knowledge of the climate variability. Using a statistical approach, we evaluate the response of the Earth’s magnetosphere to the High-Speed Solar Winds (HSSW) forcing during the peaks of the last five outer minima. To do so, 1UA data of solar wind and magnetic field parameters were extracted from OMNI browser. Analysis of the energetic solar plasma particles shows that strong geomagnetic field variations can occur even in the absence of large solar disturbances. While the normalized reconnection rate was estimated to be ~21% of the total variance of the magnetospheric variables, the upstream of the magnetic cavity was perturbed 80% of the time with large energies recorded. As a result, Earth’s magnetosphere becomes denser (i.e., more drag), which is a problem for spacecraft. Thus, the coupled solar wind-magnetosphere system follows scale-invariant dynamics and is in a state far from equilibrium. Our analysis provides insight into the main cause of geomagnetic storms with more than 97% of HSSW imposed in the range 300 - 850 km/s. These high-speeds lead to auroras that can disrupt electrical and communication systems.

日光性荨麻疹二例并文献复习

报道2例青年男性患者,面颈部、上肢日晒后红斑伴痒,行MED测定,2例患者均在30分钟内于检测部位出现红斑、风团,诊断为日光性荨麻疹。本文通过文献回顾,对日光性荨麻疹的发病机制及目前新的治疗进展进行了归纳,为该病的治疗提供新的方向。

Are Uranus &Neptune Responsible for Solar Grand Minima and Solar Cycle Modulation?

Detailed solar Angular Momentum (AM) graphs produced from the Jet Propulsion Laboratory (JPL) DE405 ephemeris display cyclic perturbations that show a very strong correlation with prior solar activity slowdowns. These same AM perturbations also occur simultaneously with known solar path changes about the Solar System Barycentre (SSB). The AM perturbations can be measured and quantified allowing analysis of past solar cycle modulations along with the 11,500 year solar proxy records (14C & 10Be). The detailed AM information also displays a recurring wave of modulation that aligns very closely with the observed sunspot record since 1650. The AM perturbation and modulation is a direct product of the outer gas giants (Uranus & Neptune). This information gives the opportunity to predict future grand minima along with normal solar cycle strength with some confidence. A proposed mechanical link between solar activity and planetary influence via a discrepancy found in solar/planet AM along with current AM perturbations indicate solar cycle 24 & 25 will be heavily reduced in sunspot activity resembling a similar pattern to solar cycles 5 & 6 during the Dalton Minimum (1790-1830).

基于岭回归的河西走廊中部日光温室低温预测模型

为了构建基于气象要素的甘肃省甘州区日光温室低温预测模型,探索应用了岭回归分析的方法。在合理选取预测因子的基础上,对预测因子之间存在的多重共线性进行诊断,为了克服预测因子共线性对模型稳定性的影响,选择岭回归分析的方法进行共线性的处理和模型构建,应用模型的预测值与实测值对模型的精度进行检验。结果表明:选取的预测因子之间存在共线性问题,通过岭回归分析建立的日光低温预测模型可以克服预测因子间由于共线性问题对模型参数造成的影响,模型预测值与实测值之间的绝对误差(≤3℃)的准确率为98.4%,决定系数(R2)为0.8543和均方根误差(RMSE)为0.7849℃,模型精度较好。基于岭回归分析法建立的日光温室低温预测模型能够对当地日光温室低温进行合理而有效的预测。

日光温室最低气温预报技术研究

为了准确预报日光温室内日最低气温,助力农户趋利避害,利用2018年—2020年冬季日光温室内外的气象观测资料,分别以温室外气温和温室外气温结合温室内气温为因子,采用逐步回归法对番茄日光温室和辣椒日光温室各建立两种最低气温预报模型。以前1 d温室外最低、最高气温和当天温室外最低、最高气温为因子建立的番茄日光温室最低气温预测模型的绝对误差(ABSE)和均方根误差(RMSE)分别为1.76℃和1.97℃,辣椒日光温室模型ABSE、,RMSE分别为1.06℃和1.31℃;以前1 d温室内外逐小时气温和当天温室外最低气温为因子建立的番茄日光温室最低气温预测模型ABSE和RMSE分别为0.44℃、0.55℃,辣椒日光温室最低气温预测模型ABSE和RBSE分别为0.52℃、0.67℃。

基于三亚VHF雷达的场向不规则体观测研究：4.太阳活动低年夏季F区回波

太阳活动低年夏季,低纬电离层F区场向不规则体表现出与太阳活动高年和其他季节明显不同的特征.本文利用我国三亚站(18.4°N,109.6°E,地磁倾角纬度dip latitude 12.8°N)VHF雷达、电离层测高仪、GPS闪烁监测仪和美国C/NOFS卫星观测数据,研究了太阳活动低年夏季我国低纬电离层F区场向不规则体的基本特征.分析发现无论磁静日还是磁扰日,夏季电离层F区不规则体回波主要出现于地方时午夜以后,回波出现的时间较短,高度范围较小,伴随着扩展F出现,但没有同时段的L波段电离层闪烁.太阳活动低年夏季午夜后的低纬电离层F区不规则体回波,可能并不总是与赤道等离子体泡沿磁力线向低纬地区的延伸相关,而可能由本地Es等扰动过程引起.

树轮资料(1511～1954)太阳活动的多尺度分析——EMD方法的应用

用EMD对Stuiver等提供的树轮^14C资料进行分析，结果为：①得到太阳活动的准3、6、11、22、44、110、200、300a的周期；从趋势项中可以得到准600a甚至更长的周期波动；②可以判断太阳活动经典的极小期，与公认的极小期有一定的滞后性。从树轮^14C含量的变化趋势中可以判断从1954～2100年的太阳活动变化逐渐变强，从2100—2350年太阳活动逐渐开始变弱；③从每个尺度周期波动的时变特征中可以得到，即使在太阳活动的极小期，太阳活动依然存在频率和强度不同的周期波动。

宁南山区日光温室内气温变化规律与最低气温预测

利用宁南山区日光温室内气温和当地气象台站的常规气象观测资料,开展了温室内气温的变化特征和温室内最低气温预测方法研究。结果表明,不同天气条件下的温室内气温日变化规律存在明显差异;温室内的日最高气温时间分布较为集中,主要出现在每日的12∶00—14∶00,而日最低气温主要出现在每日的7∶00—9∶00;温室内、外的最低气温呈现明显的线性关系,据此建立了温室内最低气温的线性回归方程,历史回代检验表明方程的预报绝对误差均在4℃以内,在2℃以内的占总数的80%以上,精度较好。

沈阳地区日光温室内最低气温变化特征及其预报模型研究

利用2013—2014年沈阳地区日光温室内和温室外的气象观测资料,采用相关分析和逐步回归分析方法对日光温室内最低气温的变化特征及其预报模型进行了研究。结果表明:2013—2014年沈阳地区日光温室内最低气温与温室外的前一日最高气温、前一日最低气温、当日最低气温及温室内前一日最高气温、前一日最低气温相关显著。沈阳地区四季不同天气条件日光温室内最低气温的预报模型存在一定的差异,冬季日光温室内最低气温模型的预报准确率较高,春季次之,秋季再次之,夏季日光温室内最低气温模型的预报效果较差,冬季、春季、秋季、夏季日光温室内日最低气温≤3.0℃的预报准确率分别为91%、85%、81%和79%;雨雪天日光温室内最低气温的预报准确率较高,阴天次之,晴天再次之,多云天日光温室内最低气温的预报准确率较低,雨雪天、阴天、晴天、多云天日光温室内日最低气温≤3.0℃的预报准确率分别为90%、87%、83%和77%。可见,本文建立的沈阳地区日光温室内最低气温模型的预报效果较好,可为沈阳地区中高档钢架砖混结构日光温室内最低气温的预报提供参考,具有较强的实用性。

太阳能热水系统集热器最佳倾角的确定

考虑系统安装的地理位置、使用时间、环境温度和系统热负荷等因素对热水系统集热量影响,给出太阳集热器最佳倾角的确定方法,并以上海临港地区为例进行计算机仿真与实验。结果表明,在太阳能热水系统补充热量最小的倾角时,才能更有效地利用冬季的太阳能资源,从而实现全年太阳能的最大利用,达到节能减排的效果。

中国南北地震带甘川段大震活动规律的讨论

中国南北地震带的甘川段（ 由甘肃通渭至四川康定） 中的７ 级以上大震多发生于太阳活动谷年及其附近。另外，该段中大震多在３５ 年的周期处和其黄金分割处发生。这些规律可供今后预测甘川段７ 级以上大震时参考。

2007-2009谷年期间高热层大气密度的变化

在第23至第24太阳活动周的峰年之间,太阳活动谷年具有持续时间长,极低F_(10.7)太阳辐射通量(低至65)和超长期的零太阳黑子数记录等特点,因此是观测和研究在这种特殊背景下热层大气变化的极好机会.尤其是能充分理解和掌握在宁静环境下热层大气密度对弱太阳活动和小地磁扰动的响应特性.本文利用高度650 km以上星载大气密度探测器2007—2009年的连续探测数据进行分析,结果表明,在太阳辐射通量F_(10.7)极低值期间,较高热层大气密度对F_(10.7)的起伏具有更显著的响应变化.当F_(10.7)由70降至65时,日均大气密度会有4～5倍的显著降变,远大于通常大气模式中的降变值.同样在F_(10.7)极低值期间,较高热层大气密度对小地磁扰动也具有显著的响应增变,当日K_p指数之和由23增至30时,较高热层大气密度则会有80%～160%的强增变.