On meandric permutations

We give a bijection between meanders and special sorts of Gauss diagrams which aroused from the Thurston generators of braid groups. It allows us to give an algorithm to construct such diagrams and to code meanders by matrices which are exactly incident matrices of the corresponding adjacency graphs of the diagrams. Finally, we show that these matrices are idempotent over the field $\mathsf{GF}(2)$, and obtain a criterion for a permutation to be meandric.