Sunspot Activity Research Articles

Solar-Cycle Characteristics in Kodaikanal Sunspot Area: North–South Asymmetry, Phase Distribution and Gnevyshev Gap

Solar activity is asymmetric in the two hemispheres in almost all cycles. This asymmetry is observed both in cycle amplitude and period. We have used about 90 years of sunspot-area data from the Kodaikanal Solar Observatory to study the north–south asymmetry in sunspot activity. The monthly mean sunspot-area showed the northern hemisphere dominated in Solar Cycles 16, 19, and 20, and the southern hemisphere dominated in Solar Cycles 18, 22, and 23. The 13-month smoothed data indicated that in Solar Cycle 17 and 21, the northern and southern hemisphere showed equal amplitude. Cumulative sunspot area showed that the northern hemisphere dominated in Solar Cycles 18, 19, 20, and 21, with a large difference between the two hemispheres in Solar Cycles 19 and 20. The northern hemisphere activity led by 12, 15, and 2 months in Solar Cycles 20, 21, and 22, respectively. No significant phase difference is found between the two hemispheres in Solar Cycles 16, 17, 18, 19, and 23. The wavelet technique is used to find Rieger-type periodicities in the sunspot cycles. The cross-wavelet analysis of these data sets showed several statistically significant common periodicities like the Rieger-type periodicities and quasi-biennial oscillations. The Gnevyshev gap was found in both the hemispheric data in Solar Cycles 16, 18, 21, 22, and 23. These results are consistent with the earlier reported characteristics of north–south asymmetry in sunspot-area data. These results suggest that the Kodaikanal Observatory data complement the existing sunspot data from other observatories to study solar activity over long and short periods.

Efficiency of Ionospheric Model Correction by Vertical-Incidence Sounding Data from an Ionosonde during Low Sunspot Activity

Numerical values of the criteria for the efficiency of the determination of the critical frequency of the F2 layer of ionosphere over European Russia are calculated with ionospheric models corrected based on vertical-incidence sounding data from an ionosonde. Two correction techniques are considered: the selection of an effective value of the input heliogeophysical index and linear-correlation correction of ionospheric models with respect to the critical frequency of the F2 layer of the ionosphere. Domains in which model correction by one point is effective are found. They determine the current coverage of the European Russia by the Russian ionospheric observation network. The regions in which the correction of median models is noticeable in comparison with the median models without correction are shown to be 7° in latitude and 15° in longitude at the midlatitudes. It is ascertained that it is mainly impossible to determine the ionospheric parameters at northern points and points in the region of the main ionospheric trough via correction based on data from midlatitude ionospheric observation sites. In these cases, the climate models without correction are more effective.

MEDIUM-TERM OSCILLATIONS OF THE SOLAR ACTIVITY

In addition to the well-known 11-year cycle, longer and shorter characteristic periods can be isolated in variations of the parameters of helio-geophysical activity. Periods of about 36 and 60 years were revealed in variations of the geomagnetic activity and an approximately 60-year periodicity, in the evolution of correlation between the pressure in the lower atmosphere and the solar activity. Similar periods are observed in the cyclonic activity. Such periods in the parameters of the solar activity are difficult to identify because of a limited database available; however, they are clearly visible in variations of the asymmetry of the sunspot activity in the northern and southern solar hemispheres. In geomagnetic variations, one can also isolate oscillations with the characteristic periods of 5-6 years (QSO) and 2-3 years (QBO). We have considered 5-6-year periodicities (about half the main cycle) observed in variations of the sunspot numbers and the intensity of the dipole component of the solar magnetic field. A comparison with different magnetic dynamo models allowed us to determine the possible origin of these oscillations. A similar result can be reproduced in a dynamo model with nonlinear parameter variations. In this case, the activity cycle turns out to be anharmonic and contains other periodicities in addition to the main one. As a result of the study, we conclude that the 5-6-year activity variations are related to the processes of nonlinear saturation of the dynamo in the solar interior. Quasi-biennial oscillations are actually separate pulses related little to each other. Therefore, the methods of the spectral analysis do not reveal them over large time intervals. They are a direct product of local fields, are generated in the near-surface layers, and are reliably recorded only in the epochs of high solar activity.

A New Singular Spectrum Decomposition Method Based on Cao Algorithm and Amplitude Aware Permutation Entropy

Singular spectrum decomposition (SSD) is relatively affected by noise. The singular spectrum component (SSC) obtained in a strong noise environment not only contains a lot of noise, but also has over-decomposition phenomenon. One reason is that the selection of the SSD embedding dimension is subjective and cannot adapt well to signals with higher complexity. Another reason is that the iterative termination condition of the SSD is based on the normalized mean square error of the residual signal and the original signal. This will cause the SSD to produce a lot of pseudo components when SSD processes strong noisy signal. In order to enhance the decomposition performance of the SSD in strong noise environment, this paper starts from the selection of embedding dimension and the improvement of iteration termination conditions, and proposes an improved singular spectrum decomposition (ISSD) based on Cao algorithm and amplitude aware permutation entropy (AAPE). Firstly, the DC of the signal to be decomposed is taken out. Secondly, Cao algorithm is used to calculate the optimal embedding dimension of the signal to be decomposed, and then SSD is performed to obtain a SSC and a residual signal. Finally, the normalized AAPE value (NAAPE) of the SSC is calculated. If it is greater than the threshold, the residual signal at this time is considered to be a noise component, the decomposition is stopped, and the residual signal is output as the last SSC. Otherwise, the residual signal is used as the signal to be decomposed, and it continues to decompose. After the decomposition, the validity of the DC (Direct component) is determined by energy comparison. If the DC is a valid component, it will be output as the first SSC. Otherwise, the DC is discarded. The completeness of ISSD through theoretical analysis and equation derivation is proved. Its effectiveness is verified by analog signal, Lorenz signal and sunspot activity data. The comparative experiment of EMD, EEMD, VMD, SSD and ISSD is used to prove the advanced nature of ISSD. The simulation results show that ISSD has the ability to identify noise and can effectively avoid over-decomposition. At the same time, ISSD can accurately extract the DC contained in the original signal to avoid energy loss. In addition, ISSD can use Cao algorithm to select the appropriate embedding dimension to improve the quality of SSC. Finally, the rank sum test is used to prove the advanced nature of ISSD from a statistical point of view.

Sunspot Activity and Coronal Holes during the Declining Phase of Cycle 24

The dynamics of coronal holes (CHs) during the declining phase of solar cycle 24 is studied based on observational data from the Atmospheric Imaging Assembly (AIA), the 19.3 nm channel, of the Solar Dynamic Observatory (SDO). Some features of changes in the areas of polar and mid- and low-latitude CHs in the period April 1, 2014–December 31, 2019, are revealed by a comparison of the variations in the daily total CH area with the index of the sunspot number. The division of all CHs observed in the considered period into polar and nonpolar shows that polar-CH areas dominate and increase while nonpolar-CH areas constantly decrease toward the cycle minimum. Polar-CH areas account for ~80% of the total area of all CHs considered over the studied period. The total polar-CH area increases toward cycle minimum, which is consistent with the general concept of polar CHs as the main source of the Sun’s dipole magnetic field. However, the second subset, which contains selected isolated CHs, shows an interesting behavior in the declining phase of solar activity that was not previously observed. Their areas slowly decrease from the maximum to minimum of the solar cycle. This trend is qualitatively consistent with a decrease in sunspot activity toward the minimum, which suggests a physical relationship between the two phenomena.

Long–Term Variations in Solar Differential Rotation and Sunspot Activity, II: Differential Rotation Around the Maxima and Minima of Solar Cycles 12 – 24

Studies of variations in the solar differential rotation are important for understanding the underlying mechanism of solar cycle and other variations of solar activity. We analyzed the sunspot-group daily data that were reported by Greenwich Photoheliographic Results (GPR) during the period 1874 – 1976 and Debrecen Photoheliographic Data (DPD) during the period 1977 – 2017. We determined the equatorial rotation rate [ $A$ ] and the latitude gradient [ $B$ ] components of the solar differential rotation by fitting the data in each of the 3-year moving time intervals (3-year MTIs) successively shifted by one year during the period 1874 – 2017 to the standard law of differential rotation. The values of $A$ and $B$ around the years of maxima and minima of Solar Cycles 12 – 24 are obtained from the 3-year MTIs series of $A$ and $B$ and studied the long-term cycle-to-cycle modulations in these coefficients. Here we have used the epochs of the maxima and minima of the Solar Cycles 12 – 24 that were recently determined from the revised Version-2 international sunspot-number series. We find that there exits a considerably significant secular decreasing-trend in $A$ around the maxima of solar cycles. There exist no secular trends in both $A$ and $B$ around the minima of solar cycles. The secular trend in $B$ around the maxima of solar cycles is also found to be statistically insignificant. We fitted a cosine function to the values of $A$ , and also to those of $B$ , after removing the corresponding linear trends. The cosine-fits suggest that there exist ≈54-year (≈94-year) and ≈82-year (≈79-year) periodicities in $A$ ( $B$ ) around the maxima and minima of solar cycles, respectively. The amplitude of the cosine-profile of $A$ ( $B$ ) around the minima of solar cycles is about 41% (65%) larger than that of $A$ ( $B$ ) around the maxima. In addition, the cosine profiles of $A$ and $B$ suggest a large (up to $180^{\circ }$ ) phase difference between the long-term variations of $A$ , and also between those of $B$ , around maxima and minima of solar cycles. Implications of all these results are discussed briefly.

Polar and Low-Latitude Faculae in Activity Cycles 23–24

Polar and low-latitude faculae were identified in daily images based on white-light observations from the MDI (1996–2011) and SOHO (2010–2019) space observatories. The boundaries of the faculae were combined with magnetic field observations at the closest possible instant of observation. The time and latitude distributions, as well as other properties of polar and low-latitude faculae, were analyzed. The resulting data on polar faculae were supplemented with observational data from Mitaka Observatory (Japan) for the period of 1951–1999. Thus, we compiled a summary series of polar activity for the period of 1951–2019. The distributions of polar faculae by area and magnetic field intensity are considered. The maximum distribution of the facula area at latitudes above θ > 55° occurs at values of approximately 6–10 mhs. The magnetic field of polar faculae has a maximum of B ~ 70–100 G. The amplitude of polar activity at the minimum in the 25th cycle approximately matches the amplitude in the 24th cycle. It can be expected that the amplitude of the sunspot activity cycle will be close to that of cycle 24.

Antarctic Winds: Pacemaker of Global Warming, Global Cooling, and the Collapse of Civilizations

We report a natural wind cycle, the Antarctic Centennial Wind Oscillation (ACWO), whose properties explain milestones of climate and human civilization, including contemporary global warming. We explored the wind/temperature relationship in Antarctica over the past 226 millennia using dust flux in ice cores from the European Project for Ice Coring in Antarctica (EPICA) Dome C (EDC) drill site as a wind proxy and stable isotopes of hydrogen and oxygen in ice cores from EDC and ten additional Antarctic drill sites as temperature proxies. The ACWO wind cycle is coupled 1:1 with the temperature cycle of the Antarctic Centennial Oscillation (ACO), the paleoclimate precursor of the contemporary Antarctic Oscillation (AAO), at all eleven drill sites over all time periods evaluated. Such tight coupling suggests that ACWO wind cycles force ACO/AAO temperature cycles. The ACWO is modulated in phase with the millennial-scale Antarctic Isotope Maximum (AIM) temperature cycle. Each AIM cycle encompasses several ACWOs that increase in frequency and amplitude to a Wind Terminus, the last and largest ACWO of every AIM cycle. This historic wind pattern, and the heat and gas exchange it forces with the Southern Ocean (SO), explains climate milestones including the Medieval Warm Period and the Little Ice Age. Contemporary global warming is explained by venting of heat and carbon dioxide from the SO forced by the maximal winds of the current positive phase of the ACO/AAO cycle. The largest 20 human civilizations of the past four millennia collapsed during or near the Little Ice Age or its earlier recurrent homologs. The Eddy Cycle of sunspot activity oscillates in phase with the AIM temperature cycle and therefore may force the internal climate cycles documented here. Climate forecasts based on the historic ACWO wind pattern project imminent global cooling and in ~4 centuries a recurrent homolog of the Little Ice Age. Our study provides a theoretically-unified explanation of contemporary global warming and other climate milestones based on natural climate cycles driven by the Sun, confirms a dominant role for climate in shaping human history, invites reconsideration of climate policy, and offers a method to project future climate.

Magnetic Coupling of the Solar Hemispheres During the Solar Cycle

This work is devoted to the study of peculiarities in the magnetic coupling of the solar hemispheres over a solar activity cycle. Two approaches have been used. We have studied (i) the magnetic coupling of active regions (ARs) located in different hemispheres in the vicinity of the central meridian and, simultaneously, in the vicinity of the equator and (ii) the properties and time variation of the meridional component of the equatorial magnetic field derived from a potential-field source surface (PFSS) reconstruction at the heliocentric distance of 1.1 solar radii. In the first case, it was shown that most of the ARs in the selected pairs were magnetically connected by field lines in their leading parts. In the second case, the magnetic field monthly mean meridional component, $B_{\theta }$ , in the equatorial plane, which magnetically connects the two hemispheres, displayed a cyclic time variation. In the process, the extreme values of $B_{\theta }$ (both positive and negative) coincided in time with the sunspot maxima, and the amplitude of the $B_{\theta }$ extreme values decreased with decreasing height of the sunspot activity cycle. The sign of the $B_{\theta }$ extreme value was opposite to the sign of the forthcoming extreme value of the polar field, while the sign of $B_{\theta }$ coincided with that of the field lines connecting the leading spots. This means that the polar field is indeed generated by the trailing spots of ARs, and the magnetic flux of the leading spots closes through the equator.

Indian summer monsoon variability in northeastern India during the last two millennia

High-resolution proxy records help to understand natural forcing of climate variability and improving our capability to predict climate variability on decadal to centennial time scales. Present study from the Mawmluh cave, northeastern India shows sudden shifts in speleothem oxygen isotope values, indicating several abrupt changes in the Indian summer monsoon (ISM) during ~212 BCE to 1986 CE. Moderate ISM conditions prevailed during ~212 BCE to 400 CE punctuated with weak intervals, strong ISM during 400 and 500 CE and from 640 to 1060 CE, whereas weak ISM conditions prevailed during 520–540 CE, 820–850 CE and 940–980 CE and after 1060 CE. The interval from 1060 to 1986 CE witnessed decreased precipitation than the previous millennium. The latter phase of the Medieval Climate Anomaly (MCA; 1060 to 1200 CE) was quite drier in contrast to the earlier intervals. The ISM was generally weak during the Little Ice Age (LIA; 1350 to 1850 CE) with short-term pulses of high precipitation when sun-spot activity was high. The data shows the weakest ISM condition during 1640–1740 CE (Maunder Minimum) of the last two millennia. Variations in extra-tropical northern hemisphere temperatures due to volcanic activity and solar insolation, and accompanying northward/southward shifting of the Inter-Tropical Convergence Zone played a pivotal role in modulating the strength of the ISM during the past two millennia.

The Solar Corona during the Total Eclipse on 1806 June 16: Graphical Evidence of the Coronal Structure during the Dalton Minimum

Abstract Visible coronal structure, in particular the spatial evolution of coronal streamers, provides indirect information about solar magnetic activity and the underlying solar dynamo. Their apparent absence of structure observed during the total eclipses throughout the Maunder minimum has been interpreted as evidence of a significant change in the solar magnetic field from that during modern solar cycles. Eclipse observations available from the more recent Dalton minimum may be able to provide further information, with sunspot activity being between the levels seen during recent solar cycles and in the Maunder minimum. Here, we show and examine two graphical records of the total solar eclipse on 1806 June 16, during the Dalton minimum. These records show significant rays and streamers around an inner ring. The ring is estimated to be ≈0.44 R ⊙ in width and the streamers in excess of 11.88 R ⊙ in length. In combination with records of spicules or prominences, these eclipse records visually contrast the Dalton minimum with the Maunder minimum in terms of their coronal structure and support the existing discussions based on the sunspot observations. These eclipse records are broadly consistent with the solar cycle phase in the modeled open solar flux and the reconstructed slow solar wind at most latitudes.

Estimation of the Ionospheric Effects of Geomagnetic Disturbances Based on Data from Wakkanai Station

Ionosonde measurements of the critical frequency of the ionospheric F2 layer (foF2) at Wakkanai station (Japan) are analyzed with the method of superposed epochs. The station is situated in a region of high seismicity. Winter periods with low sunspot and geomagnetic activity and high seismic activity are considered. The goals of this work were the quantitative characterization and comparison of ionospheric disturbances induced by the development of geomagnetic storms/geomagnetic disturbances. Geomagnetic disturbances refer to manifestations of geomagnetic activity with an intensity that is higher than “quiet” geomagnetic background but not higher than the threshold characteristic of weak geomagnetic storms. It is ascertained that weak geomagnetic storms and geomagnetic disturbances, from the time of the main trough in the Dst index after the onset of a geomagnetic storm/geomagnetic disturbance to the end of the third day, result in only positive foF2 deviations. The deviations exceed 6% of the background; the maximal relative deviations from the background (δfoF2max) are ~17% and ~14%, respectively. For geomagnetic disturbances, the most significant response of the ionosphere is observed ~7 h after the main trough in the Dst index. The resulting assessments can be used to filter out false ionospheric earthquake precursors with analysis of the ionospheric data from Wakkanai station.

A multi‐century meteo‐hydrological analysis for the Adda river basin (Central Alps). Part II: Daily runoff (1845–2016) at different scales

AbstractA high‐quality daily runoff time series of the Lake Como inflow and outflow, the longest for Italian Alps, was reconstructed for the 1845–2016 period in the Adda river basin. It was compared with contemporary monthly precipitation and temperature observations and estimated potential evapotranspiration losses. Trend analyses were conducted for daily flow maxima and 7‐day duration minima of inflows into the lake showing a non‐significant decrease and a significant increase, respectively. Although the annual precipitation time series exhibits a non‐significant decrease, annual runoff volumes decrease with a rate of −136 mm⋅century−1, with a significance level of 5%. Possible causes of variability of rainfall and runoff as North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation and Western Mediterranean Oscillation indexes and sunspot activity were also explored. Wavelet spectra analyses of monthly precipitation and runoff show some changes in the energy both at small and large scales and are effective in pointing out phenomena as droughts and the effects of dams' regulation. Conversely, wavelet coherence spectra indicate a weak correlation of NAO and sunspots with precipitation. In addition, the analysis of temperature and potential evapotranspiration tendencies suggests that the decrease of runoff has to be ascribed mostly to anthropogenic factors, including water abstraction for irrigation and increased evapotranspiration losses due to natural afforestation and, only in part, to climatic variability.

Effect of Additional Magnetograph Observations From Different Lagrangian Points in Sun‐Earth System on Predicted Properties of Quasi‐Steady Solar Wind at 1 AU

AbstractModeling the space weather conditions for a near‐Earth environment depends on a proper representation of magnetic fields on the Sun. There are discussions in the community with respect to the value of observations taken at several Lagrangian points (L1–L5) in the Sun‐Earth system. Observations from a single (e.g., Earth/L1) vantage point are insufficient to characterize rapid changes in magnetic field on the far side of the Sun. Nor can they represent well the magnetic fields near the solar poles. However, if the changes in sunspot activity were moderate, how well would our predictions of the solar wind based on a single viewing point work? How much improvement could we see by adding magnetograph observations from L5, L4, and even L3? Here, we present the results of our recent modeling, which shows the level of improvement in forecasting the properties of the solar wind at Earth made possible by using additional observations from different vantage points during a period of moderate evolution of sunspot activity. As an example, we also show the improvements to the solar wind forecast from adding a single observation of the southern polar area from out‐of‐ecliptic spacecraft at −30° heliographic latitude vantage point.

A hybrid drought index for drought assessment in Wadi Shueib catchment area in Jordan

Abstract Wadi Shueib catchment in Jordan is a water stress area and climate change is creating a further deficiency in precipitation, streamflow, and soil moisture; which are a deterrent to agriculture production in the area. In order to analyze the drought-like situation in the area, a hybrid drought index (HDI) has been developed considering the combined effect of these three variables. Fuzzy analytical hierarchy process (F-AHP) and entropy weight methods were carried out to develop a hybrid drought index (HDI) which combines meteorological, hydrological, and agricultural drought indices based on precipitation, streamflow, and soil moisture data in the area. The wavelet transform (WT) with cross wavelet (XCT) and wavelet coherence (WTC) were applied to investigate the interaction and the relations between the HDI index, drought indices, and large-scale sunspot activity Niño3.4 index. The results show that HDI can easily capture the trend of the drought-like conditions in the area based on the available data. The trend analysis of HDI revealed an increasing trend in the drought incidences in the near future. The study can be used as an early alarm for drought in the area, which can be helpful in the decision-making process towards water resources planning and management in the future.

Flux Tubes Forming Instability Near the Base of the Rotating Convection Zone: A Possible Explanation for the Low Latitudes of Sunspots

Abstract The rise of flux tubes with intense magnetic fields from the base of the convection zone to the solar surface has been substantiated as a probable mechanism for sunspot formation. The origin of flux tubes of a sufficient strength (∼105 G) is, however, uncertain. This paper considers the instability of a large-scale toroidal magnetic field caused by the magnetic suppression of convective heat transport as a candidate for the flux-tube formation mechanism. The consideration employs the analytical dependence of eddy diffusion on the magnetic field supplied by mean-field magnetohydrodynamics. The instability tends to produce regions of increased field strength with spatial scales of the order of 100 Mm at the base of the convection zone. Characteristic growth times of the instability are short compared to the 11 yr cycle. The threshold field strength for the onset of the instability increases from several hundred Gauss in the vicinity of the equator to some kilo-Gauss at middle latitudes. Growth rates of unstable disturbances decrease with latitude. These latitudinal trends can be the reason for the observed confinement of sunspot activity to a near-equatorial belt.

Multidecadal Cycles of the Climatic Index Atlantic Meridional Mode: Sunspots that Affect North and Northeast of Brazil

Using the 1951-2017 historical series of the Atlantic Meridional Mode (AMM) index and the monthly number of sunspots, it was possible to observe a significant association between them. The use of wavelet and cross-wavelet analysis showed the presence of multidecadal cycles pronounced in eleven years, as well as cycles of 2.66 and 5.33. AMM index showed, in the part of the Sea Surface Temperature (SST), the presence of a weak signal of 21.33 years. Influence and association of sunspot variability on surface temperature in Northern and Northeastern regions of Brazil were investigated. Using a non-parametric statistical correlation test, the historical series of surface temperature anomalies in five locations (Belém, São Luiz, Fortaleza, Fernando de Noronha, and Natal) were compared with the monthly solar-series anomalies. The temperature series used were the minimum monthly average, the monthly average, and maximum monthly average temperatures, with their respective anomalies in relation to the mean. However, among all the series (except for São Luiz), the analyzed minimum temperature anomalies showed a negative correlation with sunspots. As a preliminary result, the analyzed climatic indexes present an apparent degree of memory associated with the variability of sunspot activity.

Disagreement on sunspots and soybeans futures price

Disagreement on information could cause market price volatilities through the channels of gradual information flow, limited attention, and heterogeneous priors. High food price volatilities could incur severe welfare loss. This paper analyzes the effect of sunspots on the volatility of soybeans futures price in a framework of the disagreement theory. Empirically, we use the monthly time series datasets of soybeans futures price and sunspots activities from 1988-2018 to investigate how sunspots affect the volatilities of soybeans futures price by estimating the GARCH, GJR-GARCH, and Markov-switching GARCH models. Our findings can be summarized as: (1) extremely low sunspot activity could lead to both a high level and a high volatility for soybeans futures price; and (2) when considering regime changes, the disagreement level is nonlinear in the high volatility regime in which the high price volatility exists on both extremely low and high sunspot activities.

Periodic variation and phase analysis of grouped solar flare with sunspot activity

Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles. Here we report the statistical analysis of grouped solar flare (GSF) and sunspot number (SN) during the time interval from January 1965 to March 2009. We find that, (1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity, the quasi-biennial oscillation (QBO), and the eleven-year Schwabe cycle (ESC), but the specific values are not absolutely identical; (2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval, which implies that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal. Our results may provide evidence about the storage of magnetic energy in the corona.

Sunspot Positions and Areas from Observations by Thomas Harriot

The reconstruction of sunspot parameters in the early era of telescopic observations extends our knowledge on visual sunspot activity up to 400 years into the past. 200 digital solar images from 18 December 1610 to 28 January 1613 by the English astronomer Thomas Harriot were analyzed to yield sunspot counts, areas and positions. Harriot generally observed in the early morning when the Sun was near the horizon, and he specified the local time of observation, date, place, number of spots, zenith and ecliptic lines, and other information. We assigned 753 sunspots into 293 groups and defined their areas. We developed two approaches to reconstructing the heliographic coordinates of the sunspots. Method I makes use of the time of observation noted by Harriot, and Method II minimizes the day-to-day variability of sunspot latitudes independently of Harriot’s notes. The results of the two methods are discussed.