Robert Rohde

Berkeley Earth | BERKELEYEARTH

A global land–ocean temperature record has been created by combining the Berkeley Earth monthly land temperature field with spatially kriged version of the HadSST3 dataset. This combined product spans the period from 1850 to present and covers the majority of the Earth's surface: approximately 57 % in 1850, 75 % in 1880, 95 % in 1960, and 99.9 % by...

A global land/ocean temperature record has been created by combining the Berkeley Earth monthly land temperature field with spatially-kriged version of the HadSST3 dataset. This combined product spans the period from 1850 to present and covers the majority of the Earth's surface: approximately 57 % in 1850, 75 % in 1880, 95 % in 1960, and 99.9 % by...

Sea surface temperatures form a vital part of global mean surface temperature records. Historical observation methods have changed substantially over time from buckets to engine‐room intake sensors, hull sensors and drifting buoys, rendering their use for climatological studies problematic. There are substantial uncertainties in the relative biases...

Sea surface temperature (SST) records are subject to potential biases due to changing instrumentation and measurement practices. Significant differences exist between commonly used composite SST reconstructions from the National Oceanic and Atmospheric Administration’s Extended Reconstruction Sea Surface Temperature (ERSST), the Hadley Centre SST d...

The recent recognition of the environmental prevalence of perchlorate and its discovery on Mars, Earth’s moon, and in meteorites, in addition to its novel application to controlling oil reservoir sulfidogenesis, has resulted in a renewed interest in this exotic ion and its associated microbiology. However, while plentiful data exists on freshwater...

China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widesp...

Unlabelled: The pathways involved in aromatic compound oxidation under perchlorate and chlorate [collectively known as (per)chlorate]-reducing conditions are poorly understood. Previous studies suggest that these are oxygenase-dependent pathways involving O2 biogenically produced during (per)chlorate respiration. Recently, we described Sedimentico...

[1] Interannual to decadal variations in Earth global temperature estimates have often been identified with El Niño Southern Oscillation (ENSO) events. However, we show that variability on time scales of 2–15 years in mean annual global land surface temperature anomalies Tavg are more closely correlated with variability in sea surface temperatures...

An analysis team led by Anthony Watts has shown that 70% of the USHCN temperature stations are ranked in NOAA classification 4 or 5, indicating a temperature uncertainties greater than 2C or 5C, respectively. This uncertainty is large compared to the analyses of global warming, which estimate the warming of 0.64 ± 0.13 C over the period 1956 to 200...

Influence of Urban Heating on the Global Temperature Land Average using Rural Sites Identified from MODIS Classifications The effect of urban heating on estimates of global average land surface temperature is studied by applying an urban-rural classification based on MODIS satellite data to the Berkeley Earth temperature dataset compilation of 36,8...

Does urban heating effect the estimates of global average land surface temperature? We study this possible source of bias by applying an urban-rural classification based on MODIS satellite data to the Berkeley Earth temperature dataset compilation of 39,028 sites from 10 different publicly available sources. We identify a a rural subset of 16,132 s...

The Berkeley Earth Surface Temperature project has developed a new analysis framework for handling surface temperature records and constructing global temperature averages and maps. This has allowed us to achieve greater detail with less uncertainty than prior efforts. This framework adapts a weighted least-squares approach with spatial Kriging to...

The Berkeley Earth Surface Temperature team has re-evaluated the world's atmospheric land surface temperature record using a linear least-squares method that allow the use of all the digitized records back to 1800, including short records that had been excluded by prior groups. We use the Kriging method to estimate an optimal weighting of stations...

1] We develop a fully automated reconstruction of South Pole surface roughness as a measure of past wind intensity, using dynamic warping feature recognition and internal consistency checks to reduce subjectivity and analysis time. We synchronized millimeter‐ resolution optical profiles of deep South Pole glacial dust together with ice core data be...

Microbes in ice survive for > 1e5 years. With laser fluorimetry we measured tryptophan and chorophyll at mm depth intervals in cores from six glacial sites. All show a rapid decrease in Trp and Chl in the first 100 m, followed by leveling off at greater depths.

The Berkeley Fluorescence Spectrometer (BFS) was designed and implemented to provide rapid non-destructive characterizations of the organic/microbial content in glacial ice. The resulting information is general, aiming at bulk microbial concentration and a few identifiable classes of microbes, but nonetheless can provide orders of magnitude more da...

For more than three decades investigators have noticed an apparent link between volcanic eruptions and stages of glaciation during the last ice age. We have pursued a remarkable association between the onset of millennial cold phases and volcanic or volcano-like explosive fallout layers deposited in polar regions, by deploying a high-resolution opt...

We present a combination of autofluorescence studies and direct biological examinations to characterize the abundance and type of microbes in the WAIS Divide Ice Core. Rapid one-dimensional fluorescence scans were conducted on 2/3rds of the 580 meters thus far archived from WAIS Divide in order to characterize both the bulk abundance of microbes an...

We synchronize mm-scale resolution optical profiles of deep South Pole glacial dust together with ice core data between the ages 25 to 95 thousand years B.P. The images were captured with a laser dust logger deployed in six boreholes during construction of the IceCube neutrino detector array, a unique opportunity for demonstrating the potential of...

Using a spectrofluorimeter with 224-nm laser excitation and six emission bands from 300 to 420 nm to measure fluorescence intensities at 0.3-mm depth intervals in ice cores, we report results of the first comparative study of concentrations of microbial cells (using the spectrum of protein-bound tryptophan (Trp) as a proxy) and of aerosols with aut...

Using a spectrofluorimeter with 224-nm laser excitation to measure fluorescence intensity at 300-μm depth intervals, we report results of the first comparative study of concentrations of microbial cells (using the spectrum of protein-bound tryptophan (Trp) as a proxy) and of aerosols with an autofluorescence spectrum different from Trp as a functio...

Isolated spikes of anomalously high concentrations of N2O have been reported at depths in Greenland and Antarctic ice cores corresponding to narrow time intervals over the past ≈10⁵ years. Now, using a calibrated spectrofluorimeter to map protein-bound Trp, a proxy for microbes, versus depth in the 3,053-m GISP2 ice core, we find six depths at whic...

The impact risk is extremely uncertain for objects of order 0.1-1 km diameter, with kinetic energies in the range 100 to 1 million Mt (megaton TNT ~ 4×1015 J) and recurrence times estimated in thousands to many tens of thousands of years. Millennial timescales are especially interesting, since the character of explosions (e.g. impacts, large volcan...

We have developed new instruments utilizing the intrinsic fluorescence of specific biomolecules as a sensitive, non-destructive tool for detecting microorganisms. Using a 224-nm excitation, we detect protein-bound tryptophan (an amino acid present in all cells) at a detection threshold of approximately 1 cell per laser excitation volume and a duty...

Two known habitats for microbial metabolism in ice are surfaces of mineral grains and liquid veins along three- grain boundaries. Several problems suggest the need for a third habitat: veins usually contain toxic liquid; some microorganisms are too large to fit into a vein; veins may not be present at all depths; and the oxygen concentration in vei...

Two known habitats for microbial metabolism in ice are surfaces of mineral grains and liquid veins along three-grain boundaries. We propose a third, more general, habitat in which a microbe frozen in ice can metabolize by redox reactions with dissolved small molecules such as CO2, O2, N2, CO, and CH4 diffusing through the ice lattice. We show that...

The South Pole is a uniquely isolated location from which no deep ice core has yet been collected; however, by using high resolution dust logs created during the commissioning of the IceCube Neutrino Observatory we have managed to create a well resolved age versus depth relationship for this site. The dust logs (~3 mm/sample) were collected down to...

Fluorescence spectroscopy is a powerful and highly sensitive tool useful for remotely searching for sub-surface microbial life. Some ubiquitous biomolecules in microorganisms (e.g. tryptophan) have very strong and distinctive autofluorescence spectra that allow them to be optically detected at low levels even in the presence of a mineral-based fluo...

We report non-destructive detection of variability on a mm depth scale in the organic content of ice cores at NICL, as determined by the fluorescence spectrum measured by a Targeted Ultraviolet Chemical Sensor (TUCS). Many of the spectra we obtained are consistent with the amino acid tryptophan, a strongly fluorescing constituent in microbes. Ident...

Higher concentrations of dust seen in ice cores designate periods of increased glaciation and are thought to result in part from higher wind speeds due to a larger latitudinal temperature gradient. Fluctuations in air flow to a particular site are an integral part of the preserved climate record and alter the probability of detecting abrupt events...

We use argon step-release measurements to model the initial distribution of argon isotopes in 177 lunar impact spherules. The speed of modern computers permits us to approach this inverse problem in new ways, and the techniques we develop may be extended to study a wide range of samples, diffusing species, and geometries. Lunar spherules, by virtue...

As part of the commissioning of the ICECUBE Neutrino Observatory, an improved dust logger was deployed to make sub-centimeter scale measurements of ice optical properties most of the way down a 2400m South Pole borehole. These measurements, covering approximately 70,000 years, provide the highest resolution record of dust accumulation now available...

1] We describe a new dust logger designed to operate in water-filled IceCube boreholes in South Pole ice, and we give examples of its performance. We recorded optical effects due to bubbles, dust, and volcanic ash in situ from $70 to 2100 meters. Seasonal layering in bubble concentration could also be discerned. Below $1300 m over the interval 25 k...

It is well known that the diversity of life appears to fluctuate during the course of the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 million years ago). Here we show, using Sepkoski's compendium of the first and last stratigraphic appearances of 36,380 marine genera, a strong 62 +/- 3-million-year cycle...

By combining the Sepkoski Compendium of Marine Fossil Genera with the new ICS 2004 geologic time scale, we have shown that the fossil record contains a 62 +/- 3 Myr cycle in the diversity of genera. This cycle has a very high statistical significance and while the associated changes in diversity are frequently gradual, all of the sharp drops known...

Improvements in paleontology and geochronology have made it clear that the changes in biodiversity during the Phanerozoic (0-542 Ma) are not simply random but also contain strikingly periodic features. The most prominent and compelling of these is a 62 +/- 3 Myr cycle whose declines incorporate many of the mass extinctions in Earth's history. A sec...

Although cloud cover has a very strong effect on climate, its behavior is so poorly understood that its role is frequently neglected. A potential breakthrough occurred with initial reports that cloud cover could be driven by variations in cosmic rays (H. Svensmark & E. Friis-Christensen, J. Atmos. Solar-Terr. Phys. v. 59, n. 11, pp 1225-32, 1997, a...

Avalanches at the core-mantle boundary have not been directly observed, but if they exist they could affect many geophysical phenomena. Avalanches occur in ?sediment? accumulating on the inner surface of the mantle (according to the theory of Buffett et al.). Because the sediment is not evenly deposited, avalanches could provide the primary mechani...

With the recent update of the International Satellite Cloud Climatology Project's dataset, it is possible to more thoroughly examine the potential connection between the solar modulation of galactic cosmic rays and terrestrial cloud cover. Following the techniques of previous investigators, we find that the additional 5 years of data support a corr...

We use argon isotopic data from lunar impact spherules to determine relative abudances and distributions of potassium and calcium. Our observations constrain models of spherule formation.

The effect of urban heating on estimates of global average land surface temperature is studied by applying an urbanrural classification based on MODIS satellite data to the Berkeley Earth temperature data set compilation of 39,028 sites from 10 different publicly available sources. We compare the distribution of linear temperature trends for these...