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Fossil pollen records are well-established indicators of past vegetation changes. The prevalence of pollen across environmental settings including lakes, wetlands, and marine sediments, has made palynology one of the most ubiquitous and valuable tools for studying past environmental and climatic change globally for decades. A complementary research focus has been the development of statistical techniques to derive quantitative estimates of climatic conditions from pollen assemblages. This paper reviews the most commonly used statistical techniques and their rationale and seeks to provide a resource to facilitate their inclusion in more palaeoclimatic research. To this end, we first address the fundamental aspects of fossil pollen data that should be considered when undertaking pollen-based climate reconstructions. We then introduce the range of techniques currently available, the history of their development, and the situations in which they can be best employed. We reviewthe literature on how to define robust calibration datasets, produce high-quality reconstructions, and evaluate climate reconstructions, and suggest methods and products that could be developed to facilitate accessibility and global usability. To continue to foster the development and inclusion of pollen climate reconstruction methods, we promote the development of reporting standards. When established, such standards should 1) enable broader application of climate reconstruction techniques, especially in regions where such methods are currently underused, and 2) enable the evaluation and reproduction of individual reconstructions, structuring them for the evolving open-science era, and optimising the use of fossil pollen data as a vital means for the study of past environmental and climatic variability. We also strongly encourage developers and users of palaeoclimate reconstruction methodologies to make associated programming code publicly available, which will further help disseminate these techniques to interested communities.

A novel principle of low-noise voltage measurement based on microelectromechanical systems (MEMS) is introduced and experimentally demonstrated. The method is based on parametric conversion of voltage via electromechanical force to the amplitude of the RF signal of the capacitive measurement circuit that detects the displacement of a moving-plate MEMS capacitor. Both theory and experiments show that the noise of voltage measurement can be considerably decreased by biasing the MEMS device near its pull-in point. Experimental results are in agreement with theoretical predictions and they indicate the potential of the method as a competitor of state-of-the-art low-noise voltmeters in special applications.

Stability of wafer level vacuum encapsulated micromechanical resonators is characterized. The resonators are etched of silicon-on-insulator (SOI) wafers using deep reactive ion etching (DRIE) and encapsulated with anodic bonding. Bulk acoustic wave (BAW) resonator show drift better than 0.1 ppm/month demonstrating that the stability requirements for a reference oscillator can be met with MEMS. The drift of flexural resonators range from 4 ppm/month to over 500 ppm/month depending on resonator anchoring. The large drift exhibited by some flexural resonator types is attributed to packaging related stresses demonstrated by the sample temperature–frequency coefficients differing from the bulk silicon value.

Aprototype of SQUID read-out for current measurements at the output of a normal metal hot-electron microbolometer has been developed and tested. The system is based on serial VTT dc SQUID and input l-metal core solenoid transformer. The achieved current resolution is 300 fA/Hz 1=2 . Johnson noise of metal resistor and shot noise of tunnel junction were used for current calibration of SQUID read-out. The current noise spectra of 35 kX SIN tunnel junction measured at different bias voltages are presented. 2001 Elsevier Science B.V. All rights reserved.

Operation of a 14 MHz micromechanical oscillator is demonstrated and analyzed. Single-crystal silicon microbridge with submicron electrode gaps is utilized as the resonator element. The oscillator shows a noise floor of −120 dBc/Hz and a near-carrier noise of −105 dBc/Hz at 1 kHz offset. The oscillator noise is dominated by amplifier noise. By comparing the oscillator performance with conventional quartz oscillators, advantages and limitations of the micromechanical components in rf-technology are discussed.

We demonstrate a bulk acoustic mode silicon micromechanical resonator with the first eigen frequency at 12 MHz and the quality factor 180 000. Electrostatic coupling to the mechanical motion is shown to be feasible using a high bias voltage across a narrow gap. By using a low-noise preamplifier to detect the resonance, a high spectral purity oscillator is demonstrated (phase noise less than −115 dBc/Hz at 1 kHz offset from the carrier). By analyzing the constructed prototype oscillator, we discuss in detail the central performance limitations of using silicon micromechanics in oscillator applications.

Pollen analysis, the study of fossil pollen and spores, is one of the key methods for the reconstruction of past vegetation and environments. Defining the source area of pollen records is essential for the use of pollen data for precise vegetation reconstructions. Quantitative vegetation reconstruction must also account for the biases in plant–pollen representations that result from differential pollen productivity and dispersal properties. This can be achieved by using correction approaches that are based on theoretically sound models. Examples of the application of pollen analysis on various spatial and temporal scales range from reconstructions of general vegetation changes over glacial–interglacial cycles to stand-scale vegetation dynamics during the immigration of an invading species.

We have set up a system where a low-noise DC-SQUID is used as a current amplifier. The SQUID output is read using a wide band electronics unit based on the noise cancellation scheme. The SQUID has been installed in a compact Nanoway PDR50 dilution refrigerator, and superconducting transitions of Ti/Au thermometer strips for X-ray calorimeter applications have been measured. We can operate at 100 mK using a SQUID with Pd shunt resistors. Noise and bandwidth results of the setup are presented.